diff --git a/MarkMpn.Sql4Cds.Engine.Tests/AdoProviderTests.cs b/MarkMpn.Sql4Cds.Engine.Tests/AdoProviderTests.cs
index 94ad21d9..5ee77684 100644
--- a/MarkMpn.Sql4Cds.Engine.Tests/AdoProviderTests.cs
+++ b/MarkMpn.Sql4Cds.Engine.Tests/AdoProviderTests.cs
@@ -2466,5 +2466,394 @@ FROM   account AS a
                 }
             }
         }
+
+        [TestMethod]
+        public void DateTimeStringLiterals()
+        {
+            using (var con = new Sql4CdsConnection(_localDataSources))
+            using (var cmd = con.CreateCommand())
+            {
+                // https://learn.microsoft.com/en-us/sql/t-sql/data-types/date-transact-sql?view=sql-server-ver16#examples
+                cmd.CommandText = @"
+SELECT
+    CAST('2022-05-08 12:35:29.1234567 +12:15' AS TIME(7)) AS 'time',
+    CAST('2022-05-08 12:35:29.1234567 +12:15' AS DATE) AS 'date',
+    CAST('2022-05-08 12:35:29.123' AS SMALLDATETIME) AS 'smalldatetime',
+    CAST('2022-05-08 12:35:29.123' AS DATETIME) AS 'datetime',
+    CAST('2022-05-08 12:35:29.1234567 +12:15' AS DATETIME2(7)) AS 'datetime2',
+    CAST('2022-05-08 12:35:29.1234567 +12:15' AS DATETIMEOFFSET(7)) AS 'datetimeoffset';";
+
+                using (var reader = cmd.ExecuteReader())
+                {
+                    Assert.IsTrue(reader.Read());
+                    Assert.AreEqual(new TimeSpan(12, 35, 29) + TimeSpan.FromTicks(1234567), reader.GetValue(0));
+                    Assert.AreEqual(new DateTime(2022, 5, 8), reader.GetValue(1));
+                    Assert.AreEqual(new DateTime(2022, 5, 8, 12, 35, 0), reader.GetValue(2));
+                    Assert.AreEqual(new DateTime(2022, 5, 8, 12, 35, 29, 123), reader.GetValue(3));
+                    Assert.AreEqual(new DateTime(2022, 5, 8, 12, 35, 29) + TimeSpan.FromTicks(1234567), reader.GetValue(4));
+                    Assert.AreEqual(new DateTimeOffset(new DateTime(2022, 5, 8, 12, 35, 29) + TimeSpan.FromTicks(1234567), new TimeSpan(12, 15, 0)), reader.GetValue(5));
+                    Assert.IsFalse(reader.Read());
+                }
+            }
+        }
+
+        [DataTestMethod]
+        [DataRow("datetime")]
+        [DataRow("smalldatetime")]
+        public void DateTimeToNumeric(string type)
+        {
+            using (var con = new Sql4CdsConnection(_localDataSources))
+            using (var cmd = con.CreateCommand())
+            {
+                cmd.CommandText = $@"
+declare @dt {type} = '2024-10-04 12:01:00'
+select cast(@dt as float), cast(@dt as int)";
+
+                using (var reader = cmd.ExecuteReader())
+                {
+                    Assert.IsTrue(reader.Read());
+                    Assert.AreEqual(45567.500694444439, reader.GetDouble(0));
+                    Assert.AreEqual(45568, reader.GetInt32(1));
+                    Assert.IsFalse(reader.Read());
+                }
+            }
+        }
+
+        [DataTestMethod]
+        [DataRow("year", 2007)]
+        [DataRow("yyyy", 2007)]
+        [DataRow("yy", 2007)]
+        [DataRow("quarter", 4)]
+        [DataRow("qq", 4)]
+        [DataRow("q", 4)]
+        [DataRow("month", 10)]
+        [DataRow("mm", 10)]
+        [DataRow("m", 10)]
+        [DataRow("dayofyear", 303)]
+        [DataRow("dy", 303)]
+        [DataRow("y", 303)]
+        [DataRow("day", 30)]
+        [DataRow("dd", 30)]
+        [DataRow("d", 30)]
+        [DataRow("week", 44)]
+        [DataRow("wk", 44)]
+        [DataRow("ww", 44)]
+        [DataRow("weekday", 3)]
+        [DataRow("dw", 3)]
+        [DataRow("hour", 12)]
+        [DataRow("hh", 12)]
+        [DataRow("minute", 15)]
+        [DataRow("n", 15)]
+        [DataRow("second", 32)]
+        [DataRow("ss", 32)]
+        [DataRow("s", 32)]
+        [DataRow("millisecond", 123)]
+        [DataRow("ms", 123)]
+        [DataRow("microsecond", 123456)]
+        [DataRow("mcs", 123456)]
+        [DataRow("nanosecond", 123456700)]
+        [DataRow("ns", 123456700)]
+        [DataRow("tzoffset", 310)]
+        [DataRow("tz", 310)]
+        [DataRow("iso_week", 44)]
+        [DataRow("isowk", 44)]
+        [DataRow("isoww", 44)]
+        public void DatePartExamples1(string datepart, int expected)
+        {
+            // https://learn.microsoft.com/en-us/sql/t-sql/functions/datepart-transact-sql?view=sql-server-ver16#return-value
+            using (var con = new Sql4CdsConnection(_localDataSources))
+            using (var cmd = con.CreateCommand())
+            {
+                cmd.CommandText = $"SELECT DATEPART({datepart}, '2007-10-30 12:15:32.1234567 +05:10')";
+                Assert.AreEqual(expected, cmd.ExecuteScalar());
+            }
+        }
+
+        [DataTestMethod]
+        // https://learn.microsoft.com/en-us/sql/t-sql/functions/datepart-transact-sql?view=sql-server-ver16#week-and-weekday-datepart-arguments
+        // Using default SET DATEFIRST 7
+        [DataRow("week", "'2007-04-21 '", 16)]
+        [DataRow("weekday", "'2007-04-21 '", 7)]
+        // https://learn.microsoft.com/en-us/sql/t-sql/functions/datepart-transact-sql?view=sql-server-ver16#default-returned-for-a-datepart-that-isnt-in-a-date-argument
+        [DataRow("year", "'12:10:30.123'", 1900)]
+        [DataRow("month", "'12:10:30.123'", 1)]
+        [DataRow("day", "'12:10:30.123'", 1)]
+        [DataRow("dayofyear", "'12:10:30.123'", 1)]
+        [DataRow("weekday", "'12:10:30.123'", 2)]
+        // https://learn.microsoft.com/en-us/sql/t-sql/functions/datepart-transact-sql?view=sql-server-ver16#fractional-seconds
+        [DataRow("millisecond", "'00:00:01.1234567'", 123)]
+        [DataRow("microsecond", "'00:00:01.1234567'", 123456)]
+        [DataRow("nanosecond", "'00:00:01.1234567'", 123456700)]
+        // https://learn.microsoft.com/en-us/sql/t-sql/functions/datepart-transact-sql?view=sql-server-ver16#examples
+        [DataRow("year", "0", 1900)]
+        [DataRow("month", "0", 1)]
+        [DataRow("day", "0", 1)]
+        public void DatePartExamples2(string datepart, string date, int expected)
+        {
+            // Assorted examples from https://learn.microsoft.com/en-us/sql/t-sql/functions/datepart-transact-sql?view=sql-server-ver16
+            using (var con = new Sql4CdsConnection(_localDataSources))
+            using (var cmd = con.CreateCommand())
+            {
+                cmd.CommandText = $"SELECT DATEPART({datepart}, {date})";
+                Assert.AreEqual(expected, cmd.ExecuteScalar());
+            }
+        }
+
+        [DataTestMethod]
+        [DataRow("date", "day")]
+        [DataRow("smalldatetime", "hour")]
+        [DataRow("datetime", "hour")]
+        [DataRow("datetime2", "hour")]
+        [DataRow("datetimeoffset", "hour")]
+        [DataRow("time", "hour")]
+        [DataRow("varchar(100)", "hour")]
+        public void DateAddReturnsOriginalDataType(string type, string datePart)
+        {
+            using (var con = new Sql4CdsConnection(_localDataSources))
+            using (var cmd = con.CreateCommand())
+            {
+                cmd.CommandText = $@"
+DECLARE @dt {type} = '2024-10-04 12:01:02';
+SELECT DATEADD({datePart}, 1, @dt);" ;
+
+                if (type == "varchar(100)")
+                    type = "datetime";
+
+                using (var reader = cmd.ExecuteReader())
+                {
+                    var schema = reader.GetSchemaTable();
+
+                    Assert.AreEqual(type, schema.Rows[0]["DataTypeName"]);
+
+                    Assert.IsTrue(reader.Read());
+                    
+                    switch (type)
+                    {
+                        case "date":
+                            Assert.AreEqual(new DateTime(2024, 10, 5), reader.GetValue(0));
+                            break;
+
+                        case "smalldatetime":
+                            Assert.AreEqual(new DateTime(2024, 10, 4, 13, 1, 0), reader.GetValue(0));
+                            break;
+
+                        case "datetime":
+                        case "datetime2":
+                            Assert.AreEqual(new DateTime(2024, 10, 4, 13, 1, 2), reader.GetValue(0));
+                            break;
+
+                        case "datetimeoffset":
+                            Assert.AreEqual(new DateTimeOffset(2024, 10, 4, 13, 1, 2, TimeSpan.Zero), reader.GetValue(0));
+                            break;
+
+                        case "time":
+                            Assert.AreEqual(new TimeSpan(13, 1, 2), reader.GetValue(0));
+                            break;
+                    }
+
+                    Assert.IsFalse(reader.Read());
+                }
+            }
+        }
+
+        [DataTestMethod]
+        [DataRow("date", "month")]
+        [DataRow("smalldatetime", "hour")]
+        [DataRow("datetime", "hour")]
+        [DataRow("datetime2", "hour")]
+        [DataRow("datetimeoffset", "hour")]
+        [DataRow("time", "hour")]
+        [DataRow("varchar(100)", "hour")]
+        public void DateTruncReturnsOriginalDataType(string type, string datePart)
+        {
+            using (var con = new Sql4CdsConnection(_localDataSources))
+            using (var cmd = con.CreateCommand())
+            {
+                cmd.CommandText = $@"
+DECLARE @dt {type} = '2024-10-04 12:01:02';
+SELECT DATETRUNC({datePart}, @dt);";
+
+                if (type == "varchar(100)")
+                    type = "datetime2";
+
+                using (var reader = cmd.ExecuteReader())
+                {
+                    var schema = reader.GetSchemaTable();
+
+                    Assert.AreEqual(type, schema.Rows[0]["DataTypeName"]);
+
+                    Assert.IsTrue(reader.Read());
+
+                    switch (type)
+                    {
+                        case "date":
+                            Assert.AreEqual(new DateTime(2024, 10, 1), reader.GetValue(0));
+                            break;
+
+                        case "smalldatetime":
+                            Assert.AreEqual(new DateTime(2024, 10, 4, 12, 0, 0), reader.GetValue(0));
+                            break;
+
+                        case "datetime":
+                        case "datetime2":
+                            Assert.AreEqual(new DateTime(2024, 10, 4, 12, 0, 0), reader.GetValue(0));
+                            break;
+
+                        case "datetimeoffset":
+                            Assert.AreEqual(new DateTimeOffset(2024, 10, 4, 12, 0, 0, TimeSpan.Zero), reader.GetValue(0));
+                            break;
+
+                        case "time":
+                            Assert.AreEqual(new TimeSpan(12, 0, 0), reader.GetValue(0));
+                            break;
+                    }
+
+                    Assert.IsFalse(reader.Read());
+                }
+            }
+        }
+
+        [TestMethod]
+        public void DateDiffString()
+        {
+            // https://learn.microsoft.com/en-us/sql/t-sql/functions/datediff-transact-sql?view=sql-server-ver16#i-finding-difference-between-startdate-and-enddate-as-date-parts-strings
+            using (var con = new Sql4CdsConnection(_localDataSources))
+            using (var cmd = con.CreateCommand())
+            {
+                cmd.CommandText = @"
+-- DOES NOT ACCOUNT FOR LEAP YEARS
+DECLARE @date1 DATETIME, @date2 DATETIME, @result VARCHAR(100);
+DECLARE @years INT, @months INT, @days INT,
+    @hours INT, @minutes INT, @seconds INT, @milliseconds INT;
+
+SET @date1 = '1900-01-01 00:00:00.000'
+SET @date2 = '2018-12-12 07:08:01.123'
+
+SELECT @years = DATEDIFF(yy, @date1, @date2)
+IF DATEADD(yy, -@years, @date2) < @date1 
+SELECT @years = @years-1
+SET @date2 = DATEADD(yy, -@years, @date2)
+
+SELECT @months = DATEDIFF(mm, @date1, @date2)
+IF DATEADD(mm, -@months, @date2) < @date1 
+SELECT @months=@months-1
+SET @date2= DATEADD(mm, -@months, @date2)
+
+SELECT @days=DATEDIFF(dd, @date1, @date2)
+IF DATEADD(dd, -@days, @date2) < @date1 
+SELECT @days=@days-1
+SET @date2= DATEADD(dd, -@days, @date2)
+
+SELECT @hours=DATEDIFF(hh, @date1, @date2)
+IF DATEADD(hh, -@hours, @date2) < @date1 
+SELECT @hours=@hours-1
+SET @date2= DATEADD(hh, -@hours, @date2)
+
+SELECT @minutes=DATEDIFF(mi, @date1, @date2)
+IF DATEADD(mi, -@minutes, @date2) < @date1 
+SELECT @minutes=@minutes-1
+SET @date2= DATEADD(mi, -@minutes, @date2)
+
+SELECT @seconds=DATEDIFF(s, @date1, @date2)
+IF DATEADD(s, -@seconds, @date2) < @date1 
+SELECT @seconds=@seconds-1
+SET @date2= DATEADD(s, -@seconds, @date2)
+
+SELECT @milliseconds=DATEDIFF(ms, @date1, @date2)
+
+SELECT @result= ISNULL(CAST(NULLIF(@years,0) AS VARCHAR(10)) + ' years,','')
+     + ISNULL(' ' + CAST(NULLIF(@months,0) AS VARCHAR(10)) + ' months,','')    
+     + ISNULL(' ' + CAST(NULLIF(@days,0) AS VARCHAR(10)) + ' days,','')
+     + ISNULL(' ' + CAST(NULLIF(@hours,0) AS VARCHAR(10)) + ' hours,','')
+     + ISNULL(' ' + CAST(@minutes AS VARCHAR(10)) + ' minutes and','')
+     + ISNULL(' ' + CAST(@seconds AS VARCHAR(10)) 
+     + CASE
+            WHEN @milliseconds > 0
+                THEN '.' + CAST(@milliseconds AS VARCHAR(10)) 
+            ELSE ''
+       END 
+     + ' seconds','')
+
+SELECT @result";
+
+                var actual = (string)cmd.ExecuteScalar();
+                Assert.AreEqual("118 years, 11 months, 11 days, 7 hours, 8 minutes and 1.123 seconds", actual);
+            }
+        }
+
+        [DataTestMethod]
+        [DataRow("datetimeoffset", ".1234567")]
+        [DataRow("datetimeoffset(4)", ".1235")]
+        [DataRow("datetimeoffset(0)", "")]
+        public void DateTimeOffsetToString(string type, string suffix)
+        {
+            using (var con = new Sql4CdsConnection(_localDataSources))
+            using (var cmd = con.CreateCommand())
+            {
+                cmd.CommandText = $"SELECT CAST(CAST('2024-10-04 12:01:02.1234567 +05:10' AS {type}) AS VARCHAR(100))";
+
+                var actual = (string)cmd.ExecuteScalar();
+                Assert.AreEqual($"2024-10-04 12:01:02{suffix} +05:10", actual);
+            }
+        }
+
+        [DataTestMethod]
+        [DataRow("mdy", "2003-01-02")]
+        [DataRow("dmy", "2003-02-01")]
+        [DataRow("ymd", "2001-02-03")]
+        [DataRow("ydm", "2001-03-02")]
+        [DataRow("myd", "2002-01-03")]
+        [DataRow("dym", "2002-03-01")]
+        public void SetDataFormat(string format, string expected)
+        {
+            using (var con = new Sql4CdsConnection(_localDataSources))
+            using (var cmd = con.CreateCommand())
+            {
+                cmd.CommandText = $@"
+SET DATEFORMAT {format};
+SELECT CAST('01/02/03' AS DATETIME)";
+
+                var actual = (DateTime)cmd.ExecuteScalar();
+                Assert.AreEqual(DateTime.ParseExact(expected, "yyyy-MM-dd", CultureInfo.InvariantCulture), actual);
+            }
+        }
+
+        [TestMethod]
+        public void ErrorNumberPersistedBetweenExecutions()
+        {
+            using (var con = new Sql4CdsConnection(_localDataSources))
+            {
+                using (var cmd = con.CreateCommand())
+                {
+                    try
+                    {
+                        cmd.CommandText = "SELECT 1/0";
+                        cmd.ExecuteScalar();
+                        Assert.Fail();
+                    }
+                    catch (Sql4CdsException ex)
+                    {
+                        if (ex.Number != 8134)
+                            Assert.Fail();
+                    }
+                }
+
+                using (var cmd = con.CreateCommand())
+                {
+                    // Error should be persisted in the connection session from the previous command
+                    cmd.CommandText = "SELECT @@ERROR";
+                    var error = (int)cmd.ExecuteScalar();
+                    Assert.AreEqual(8134, error);
+                }
+
+                using (var cmd = con.CreateCommand())
+                {
+                    // Error should be reset by the previous execution
+                    cmd.CommandText = "SELECT @@ERROR";
+                    var error = (int)cmd.ExecuteScalar();
+                    Assert.AreEqual(0, error);
+                }
+            }
+        }
     }
 }
diff --git a/MarkMpn.Sql4Cds.Engine.Tests/CteTests.cs b/MarkMpn.Sql4Cds.Engine.Tests/CteTests.cs
index 65b2ad49..c29082a4 100644
--- a/MarkMpn.Sql4Cds.Engine.Tests/CteTests.cs
+++ b/MarkMpn.Sql4Cds.Engine.Tests/CteTests.cs
@@ -46,6 +46,8 @@ public class CteTests : FakeXrmEasyTestsBase, IQueryExecutionOptions
 
         bool IQueryExecutionOptions.BypassCustomPlugins => false;
 
+        public event EventHandler PrimaryDataSourceChanged;
+
         void IQueryExecutionOptions.ConfirmInsert(ConfirmDmlStatementEventArgs e)
         {
         }
@@ -78,7 +80,7 @@ void IQueryExecutionOptions.Progress(double? progress, string message)
         [TestMethod]
         public void SimpleSelect()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 WITH cte AS (SELECT accountid, name FROM account)
@@ -102,7 +104,7 @@ WITH cte AS (SELECT accountid, name FROM account)
         [TestMethod]
         public void ColumnAliases()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 WITH cte (id, n) AS (SELECT accountid, name FROM account)
@@ -126,7 +128,7 @@ WITH cte (id, n) AS (SELECT accountid, name FROM account)
         [TestMethod]
         public void MultipleAnchorQueries()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 WITH cte (id, n) AS (SELECT accountid, name FROM account UNION ALL select contactid, fullname FROM contact)
@@ -159,7 +161,7 @@ WITH cte (id, n) AS (SELECT accountid, name FROM account UNION ALL select contac
         [TestMethod]
         public void MergeFilters()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 WITH cte AS (SELECT contactid, firstname, lastname FROM contact WHERE firstname = 'Mark')
@@ -188,7 +190,7 @@ WITH cte AS (SELECT contactid, firstname, lastname FROM contact WHERE firstname
         [TestMethod]
         public void MultipleReferencesWithAliases()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 WITH cte AS (SELECT contactid, firstname, lastname FROM contact WHERE firstname = 'Mark')
@@ -226,7 +228,7 @@ WITH cte AS (SELECT contactid, firstname, lastname FROM contact WHERE firstname
         [TestMethod]
         public void MultipleReferencesInUnionAll()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 WITH cte AS (SELECT contactid, firstname, lastname FROM contact WHERE firstname = 'Mark')
@@ -262,7 +264,7 @@ WITH cte AS (SELECT contactid, firstname, lastname FROM contact WHERE firstname
         [ExpectedException(typeof(NotSupportedQueryFragmentException))]
         public void MultipleRecursiveReferences()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 WITH cte AS (
@@ -279,7 +281,7 @@ UNION ALL
         [ExpectedException(typeof(NotSupportedQueryFragmentException))]
         public void HintsOnRecursiveReference()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 WITH cte AS (
@@ -296,7 +298,7 @@ UNION ALL
         [ExpectedException(typeof(NotSupportedQueryFragmentException))]
         public void RecursionWithoutUnionAll()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 WITH cte AS (
@@ -313,7 +315,7 @@ SELECT cte.* FROM cte
         [ExpectedException(typeof(QueryParseException))]
         public void OrderByWithoutTop()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 WITH cte AS (
@@ -331,7 +333,7 @@ ORDER BY firstname
         [ExpectedException(typeof(NotSupportedQueryFragmentException))]
         public void GroupByOnRecursiveReference()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 WITH cte AS (
@@ -348,7 +350,7 @@ UNION ALL
         [ExpectedException(typeof(NotSupportedQueryFragmentException))]
         public void AggregateOnRecursiveReference()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 WITH cte AS (
@@ -365,7 +367,7 @@ SELECT MIN(contactid), MIN(firstname), MIN(lastname) FROM cte
         [ExpectedException(typeof(NotSupportedQueryFragmentException))]
         public void TopOnRecursiveReference()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 WITH cte AS (
@@ -382,7 +384,7 @@ SELECT TOP 10 cte.* FROM cte
         [ExpectedException(typeof(NotSupportedQueryFragmentException))]
         public void OuterJoinOnRecursiveReference()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 WITH cte AS (
@@ -399,7 +401,7 @@ UNION ALL
         [ExpectedException(typeof(NotSupportedQueryFragmentException))]
         public void SubqueryOnRecursiveReference()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 WITH cte AS (
@@ -416,7 +418,7 @@ UNION ALL
         [ExpectedException(typeof(NotSupportedQueryFragmentException))]
         public void IncorrectColumnCount()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 WITH cte (id, fname) AS (
@@ -431,7 +433,7 @@ WITH cte (id, fname) AS (
         [ExpectedException(typeof(NotSupportedQueryFragmentException))]
         public void AnonymousColumn()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 WITH cte AS (
@@ -446,7 +448,7 @@ WITH cte AS (
         [ExpectedException(typeof(NotSupportedQueryFragmentException))]
         public void MissingAnchorQuery()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 WITH cte (x, y) AS (
@@ -460,7 +462,7 @@ WITH cte (x, y) AS (
         [TestMethod]
         public void AliasedAnonymousColumn()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 WITH cte (id, fname, lname) AS (
@@ -498,7 +500,7 @@ WITH cte (id, fname, lname) AS (
         [TestMethod]
         public void SelectStarFromValues()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 WITH source_data_cte AS (
@@ -535,7 +537,7 @@ WITH source_data_cte AS (
         [TestMethod]
         public void SimpleRecursion()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 WITH cte AS (
@@ -675,7 +677,7 @@ union all
         [TestMethod]
         public void Under()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 WITH account_hierarchical(accountid) AS (
@@ -706,7 +708,7 @@ UNION ALL
         [TestMethod]
         public void EqOrUnder()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 WITH account_hierarchical(accountid) AS (
@@ -737,7 +739,7 @@ UNION ALL
         [TestMethod]
         public void Above()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 WITH account_hierarchical(accountid, parentaccountid) AS (
@@ -768,7 +770,7 @@ UNION ALL
         [TestMethod]
         public void EqOrAbove()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 WITH account_hierarchical(accountid, parentaccountid) AS (
diff --git a/MarkMpn.Sql4Cds.Engine.Tests/ExecutionPlanNodeTests.cs b/MarkMpn.Sql4Cds.Engine.Tests/ExecutionPlanNodeTests.cs
index 86dbaf33..cf5050d0 100644
--- a/MarkMpn.Sql4Cds.Engine.Tests/ExecutionPlanNodeTests.cs
+++ b/MarkMpn.Sql4Cds.Engine.Tests/ExecutionPlanNodeTests.cs
@@ -37,7 +37,7 @@ public void ConstantScanTest()
                 Alias = "test"
             };
 
-            var results = node.Execute(new NodeExecutionContext(_localDataSources, new StubOptions(), null, null, null)).ToArray();
+            var results = node.Execute(new NodeExecutionContext(new SessionContext(_localDataSources, new StubOptions()), new StubOptions(), null, null, null)).ToArray();
             
             Assert.AreEqual(1, results.Length);
             Assert.AreEqual("Mark", ((SqlString)results[0]["test.firstname"]).Value);
@@ -84,7 +84,7 @@ public void FilterNodeTest()
                 }
             };
 
-            var results = node.Execute(new NodeExecutionContext(_localDataSources, new StubOptions(), null, null, null)).ToArray();
+            var results = node.Execute(new NodeExecutionContext(new SessionContext(_localDataSources, new StubOptions()), new StubOptions(), null, null, null)).ToArray();
 
             Assert.AreEqual(1, results.Length);
             Assert.AreEqual("Mark", ((SqlString)results[0]["test.firstname"]).Value);
@@ -161,7 +161,7 @@ public void MergeJoinInnerTest()
                 JoinType = QualifiedJoinType.Inner
             };
 
-            var results = node.Execute(new NodeExecutionContext(_localDataSources, new StubOptions(), null, null, null)).ToArray();
+            var results = node.Execute(new NodeExecutionContext(new SessionContext(_localDataSources, new StubOptions()), new StubOptions(), null, null, null)).ToArray();
 
             Assert.AreEqual(2, results.Length);
             Assert.AreEqual("Mark", ((SqlString)results[0]["f.firstname"]).Value);
@@ -241,7 +241,7 @@ public void MergeJoinLeftOuterTest()
                 JoinType = QualifiedJoinType.LeftOuter
             };
 
-            var results = node.Execute(new NodeExecutionContext(_localDataSources, new StubOptions(), null, null, null)).ToArray();
+            var results = node.Execute(new NodeExecutionContext(new SessionContext(_localDataSources, new StubOptions()), new StubOptions(), null, null, null)).ToArray();
 
             Assert.AreEqual(3, results.Length);
             Assert.AreEqual("Mark", ((SqlString)results[0]["f.firstname"]).Value);
@@ -323,7 +323,7 @@ public void MergeJoinRightOuterTest()
                 JoinType = QualifiedJoinType.RightOuter
             };
 
-            var results = node.Execute(new NodeExecutionContext(_localDataSources, new StubOptions(), null, null, null)).ToArray();
+            var results = node.Execute(new NodeExecutionContext(new SessionContext(_localDataSources, new StubOptions()), new StubOptions(), null, null, null)).ToArray();
 
             Assert.AreEqual(3, results.Length);
             Assert.AreEqual("Mark", ((SqlString)results[0]["f.firstname"]).Value);
@@ -362,7 +362,7 @@ public void AssertionTest()
                 ErrorMessage = "Only Mark is allowed"
             };
 
-            var results = node.Execute(new NodeExecutionContext(_localDataSources, new StubOptions(), null, null, null)).GetEnumerator();
+            var results = node.Execute(new NodeExecutionContext(new SessionContext(_localDataSources, new StubOptions()), new StubOptions(), null, null, null)).GetEnumerator();
 
             Assert.IsTrue(results.MoveNext());
             Assert.AreEqual("Mark", results.Current.GetAttributeValue<SqlString>("test.name").Value);
@@ -420,7 +420,7 @@ public void ComputeScalarTest()
                 }
             };
 
-            var results = node.Execute(new NodeExecutionContext(_localDataSources, new StubOptions(), null, null, null))
+            var results = node.Execute(new NodeExecutionContext(new SessionContext(_localDataSources, new StubOptions()), new StubOptions(), null, null, null))
                 .Select(e => e.GetAttributeValue<SqlInt32>("mul").Value)
                 .ToArray();
 
@@ -462,7 +462,7 @@ public void DistinctTest()
                 }
             };
 
-            var results = node.Execute(new NodeExecutionContext(_localDataSources, new StubOptions(), null, null, null))
+            var results = node.Execute(new NodeExecutionContext(new SessionContext(_localDataSources, new StubOptions()), new StubOptions(), null, null, null))
                 .Select(e => e.GetAttributeValue<SqlInt32>("test.value1").Value)
                 .ToArray();
 
@@ -504,7 +504,7 @@ public void DistinctCaseInsensitiveTest()
                 }
             };
 
-            var results = node.Execute(new NodeExecutionContext(_localDataSources, new StubOptions(), null, null, null))
+            var results = node.Execute(new NodeExecutionContext(new SessionContext(_localDataSources, new StubOptions()), new StubOptions(), null, null, null))
                 .Select(e => e.GetAttributeValue<SqlString>("test.value1").Value)
                 .ToArray();
 
@@ -562,7 +562,7 @@ public void SortNodeTest()
                 }
             };
 
-            var results = node.Execute(new NodeExecutionContext(_localDataSources, new StubOptions(), null, null, null))
+            var results = node.Execute(new NodeExecutionContext(new SessionContext(_localDataSources, new StubOptions()), new StubOptions(), null, null, null))
                 .Select(e => e.GetAttributeValue<SqlInt32>("test.expectedorder").Value)
                 .ToArray();
 
@@ -627,7 +627,7 @@ public void SortNodePresortedTest()
                 }
             };
 
-            var results = node.Execute(new NodeExecutionContext(_localDataSources, new StubOptions(), null, null, null))
+            var results = node.Execute(new NodeExecutionContext(new SessionContext(_localDataSources, new StubOptions()), new StubOptions(), null, null, null))
                 .Select(e => e.GetAttributeValue<SqlInt32>("test.expectedorder").Value)
                 .ToArray();
 
@@ -659,11 +659,11 @@ public void TableSpoolTest()
 
             var spool = new TableSpoolNode { Source = source };
 
-            var results1 = spool.Execute(new NodeExecutionContext(_localDataSources, new StubOptions(), null, null, null))
+            var results1 = spool.Execute(new NodeExecutionContext(new SessionContext(_localDataSources, new StubOptions()), new StubOptions(), null, null, null))
                 .Select(e => e.GetAttributeValue<SqlInt32>("test.value1").Value)
                 .ToArray();
 
-            var results2 = spool.Execute(new NodeExecutionContext(_localDataSources, new StubOptions(), null, null, null))
+            var results2 = spool.Execute(new NodeExecutionContext(new SessionContext(_localDataSources, new StubOptions()), new StubOptions(), null, null, null))
                 .Select(e => e.GetAttributeValue<SqlInt32>("test.value1").Value)
                 .ToArray();
 
@@ -708,7 +708,7 @@ public void CaseInsenstiveHashMatchAggregateNodeTest()
                 }
             };
 
-            var results = spool.Execute(new NodeExecutionContext(_localDataSources, new StubOptions(), null, null, null))
+            var results = spool.Execute(new NodeExecutionContext(new SessionContext(_localDataSources, new StubOptions()), new StubOptions(), null, null, null))
                 .Select(e => new { Name = e.GetAttributeValue<SqlString>("src.value1").Value, Count = e.GetAttributeValue<SqlInt32>("count").Value })
                 .ToArray();
 
@@ -719,7 +719,7 @@ public void CaseInsenstiveHashMatchAggregateNodeTest()
         public void SqlTransformSchemaOnly()
         {
             var sql = "SELECT name FROM account; DECLARE @id uniqueidentifier; SELECT name FROM account WHERE accountid = @id";
-            var transformed = SqlNode.ApplyCommandBehavior(sql, System.Data.CommandBehavior.SchemaOnly, new StubOptions());
+            var transformed = SqlNode.ApplyCommandBehavior(sql, System.Data.CommandBehavior.SchemaOnly, new NodeExecutionContext(new SessionContext(_localDataSources, new StubOptions()), new StubOptions(), null, null, null));
             transformed = Regex.Replace(transformed, "[ \\r\\n]+", " ").Trim();
 
             Assert.AreEqual("SELECT name FROM account WHERE 0 = 1; DECLARE @id AS UNIQUEIDENTIFIER; SELECT name FROM account WHERE accountid = @id AND 0 = 1;", transformed);
@@ -729,7 +729,7 @@ public void SqlTransformSchemaOnly()
         public void SqlTransformSingleRow()
         {
             var sql = "SELECT name FROM account; DECLARE @id uniqueidentifier; SELECT name FROM account WHERE accountid = @id";
-            var transformed = SqlNode.ApplyCommandBehavior(sql, System.Data.CommandBehavior.SingleRow, new StubOptions());
+            var transformed = SqlNode.ApplyCommandBehavior(sql, System.Data.CommandBehavior.SingleRow, new NodeExecutionContext(new SessionContext(_localDataSources, new StubOptions()), new StubOptions(), null, null, null));
             transformed = Regex.Replace(transformed, "[ \\r\\n]+", " ").Trim();
 
             Assert.AreEqual("SELECT TOP 1 name FROM account; DECLARE @id AS UNIQUEIDENTIFIER;", transformed);
@@ -739,7 +739,7 @@ public void SqlTransformSingleRow()
         public void SqlTransformSingleResult()
         {
             var sql = "SELECT name FROM account; DECLARE @id uniqueidentifier; SELECT name FROM account WHERE accountid = @id";
-            var transformed = SqlNode.ApplyCommandBehavior(sql, System.Data.CommandBehavior.SingleResult, new StubOptions());
+            var transformed = SqlNode.ApplyCommandBehavior(sql, System.Data.CommandBehavior.SingleResult, new NodeExecutionContext(new SessionContext(_localDataSources, new StubOptions()), new StubOptions(), null, null, null));
             transformed = Regex.Replace(transformed, "[ \\r\\n]+", " ").Trim();
 
             Assert.AreEqual("SELECT name FROM account; DECLARE @id AS UNIQUEIDENTIFIER;", transformed);
@@ -749,7 +749,7 @@ public void SqlTransformSingleResult()
         public void AggregateInitialTest()
         {
             var aggregate = CreateAggregateTest();
-            var result = aggregate.Execute(new NodeExecutionContext(_localDataSources, new StubOptions(), null, null, null)).Single();
+            var result = aggregate.Execute(new NodeExecutionContext(new SessionContext(_localDataSources, new StubOptions()), new StubOptions(), null, null, null)).Single();
 
             Assert.AreEqual(SqlInt32.Null, result["min"]);
             Assert.AreEqual(SqlInt32.Null, result["max"]);
@@ -767,7 +767,7 @@ public void AggregateInitialTest()
         public void AggregateSingleValueTest()
         {
             var aggregate = CreateAggregateTest(1);
-            var result = aggregate.Execute(new NodeExecutionContext(_localDataSources, new StubOptions(), null, null, null)).Single();
+            var result = aggregate.Execute(new NodeExecutionContext(new SessionContext(_localDataSources, new StubOptions()), new StubOptions(), null, null, null)).Single();
 
             Assert.AreEqual((SqlInt32)1, result["min"]);
             Assert.AreEqual((SqlInt32)1, result["max"]);
@@ -785,7 +785,7 @@ public void AggregateSingleValueTest()
         public void AggregateTwoEqualValuesTest()
         {
             var aggregate = CreateAggregateTest(1, 1);
-            var result = aggregate.Execute(new NodeExecutionContext(_localDataSources, new StubOptions(), null, null, null)).Single();
+            var result = aggregate.Execute(new NodeExecutionContext(new SessionContext(_localDataSources, new StubOptions()), new StubOptions(), null, null, null)).Single();
 
             Assert.AreEqual((SqlInt32)1, result["min"]);
             Assert.AreEqual((SqlInt32)1, result["max"]);
@@ -803,7 +803,7 @@ public void AggregateTwoEqualValuesTest()
         public void AggregateMultipleValuesTest()
         {
             var aggregate = CreateAggregateTest(1, 3, 1, 1);
-            var result = aggregate.Execute(new NodeExecutionContext(_localDataSources, new StubOptions(), null, null, null)).Single();
+            var result = aggregate.Execute(new NodeExecutionContext(new SessionContext(_localDataSources, new StubOptions()), new StubOptions(), null, null, null)).Single();
 
             Assert.AreEqual((SqlInt32)1, result["min"]);
             Assert.AreEqual((SqlInt32)3, result["max"]);
@@ -962,7 +962,7 @@ public void NestedLoopJoinInnerTest()
                 }
             };
 
-            var results = node.Execute(new NodeExecutionContext(_localDataSources, new StubOptions(), null, null, null)).ToArray();
+            var results = node.Execute(new NodeExecutionContext(new SessionContext(_localDataSources, new StubOptions()), new StubOptions(), null, null, null)).ToArray();
 
             Assert.AreEqual(2, results.Length);
             Assert.AreEqual("Mark", ((SqlString)results[0]["f.firstname"]).Value);
@@ -1034,7 +1034,7 @@ public void NestedLoopJoinLeftOuterTest()
                 }
             };
 
-            var results = node.Execute(new NodeExecutionContext(_localDataSources, new StubOptions(), null, null, null)).ToArray();
+            var results = node.Execute(new NodeExecutionContext(new SessionContext(_localDataSources, new StubOptions()), new StubOptions(), null, null, null)).ToArray();
 
             Assert.AreEqual(3, results.Length);
             Assert.AreEqual("Mark", ((SqlString)results[0]["f.firstname"]).Value);
@@ -1068,7 +1068,7 @@ public void FetchXmlSingleTablePrimaryKey()
                     }
                 }
             };
-            var schema = fetch.GetSchema(new NodeCompilationContext(_localDataSources, new StubOptions(), null, null));
+            var schema = fetch.GetSchema(new NodeCompilationContext(new SessionContext(_localDataSources, new StubOptions()), new StubOptions(), null, null));
             Assert.AreEqual("account.accountid", schema.PrimaryKey);
         }
 
@@ -1108,7 +1108,7 @@ public void FetchXmlChildTablePrimaryKey()
                     }
                 }
             };
-            var schema = fetch.GetSchema(new NodeCompilationContext(_localDataSources, new StubOptions(), null, null));
+            var schema = fetch.GetSchema(new NodeCompilationContext(new SessionContext(_localDataSources, new StubOptions()), new StubOptions(), null, null));
             Assert.AreEqual("contact.contactid", schema.PrimaryKey);
         }
 
@@ -1148,7 +1148,7 @@ public void FetchXmlChildTableOuterJoinPrimaryKey()
                     }
                 }
             };
-            var schema = fetch.GetSchema(new NodeCompilationContext(_localDataSources, new StubOptions(), null, null));
+            var schema = fetch.GetSchema(new NodeCompilationContext(new SessionContext(_localDataSources, new StubOptions()), new StubOptions(), null, null));
             Assert.IsNull(schema.PrimaryKey);
         }
 
@@ -1188,7 +1188,7 @@ public void FetchXmlParentTablePrimaryKey()
                     }
                 }
             };
-            var schema = fetch.GetSchema(new NodeCompilationContext(_localDataSources, new StubOptions(), null, null));
+            var schema = fetch.GetSchema(new NodeCompilationContext(new SessionContext(_localDataSources, new StubOptions()), new StubOptions(), null, null));
             Assert.AreEqual("account.accountid", schema.PrimaryKey);
         }
 
@@ -1228,7 +1228,7 @@ public void FetchXmlParentTableOuterJoinPrimaryKey()
                     }
                 }
             };
-            var schema = fetch.GetSchema(new NodeCompilationContext(_localDataSources, new StubOptions(), null, null));
+            var schema = fetch.GetSchema(new NodeCompilationContext(new SessionContext(_localDataSources, new StubOptions()), new StubOptions(), null, null));
             Assert.AreEqual("account.accountid", schema.PrimaryKey);
         }
 
@@ -1268,7 +1268,7 @@ public void FetchXmlChildTableFreeTextJoinPrimaryKey()
                     }
                 }
             };
-            var schema = fetch.GetSchema(new NodeCompilationContext(_localDataSources, new StubOptions(), null, null));
+            var schema = fetch.GetSchema(new NodeCompilationContext(new SessionContext(_localDataSources, new StubOptions()), new StubOptions(), null, null));
             Assert.IsNull(schema.PrimaryKey);
         }
     }
diff --git a/MarkMpn.Sql4Cds.Engine.Tests/ExecutionPlanTests.cs b/MarkMpn.Sql4Cds.Engine.Tests/ExecutionPlanTests.cs
index 33827bb5..160a7df0 100644
--- a/MarkMpn.Sql4Cds.Engine.Tests/ExecutionPlanTests.cs
+++ b/MarkMpn.Sql4Cds.Engine.Tests/ExecutionPlanTests.cs
@@ -46,6 +46,8 @@ public class ExecutionPlanTests : FakeXrmEasyTestsBase, IQueryExecutionOptions
 
         bool IQueryExecutionOptions.BypassCustomPlugins => false;
 
+        public event EventHandler PrimaryDataSourceChanged;
+
         void IQueryExecutionOptions.ConfirmInsert(ConfirmDmlStatementEventArgs e)
         {
         }
@@ -78,7 +80,7 @@ void IQueryExecutionOptions.Progress(double? progress, string message)
         [TestMethod]
         public void SimpleSelect()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = "SELECT accountid, name FROM account";
 
@@ -100,7 +102,7 @@ public void SimpleSelect()
         [TestMethod]
         public void SimpleSelectStar()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = "SELECT * FROM account";
 
@@ -136,7 +138,7 @@ public void SimpleSelectStar()
         [TestMethod]
         public void Join()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = "SELECT accountid, name FROM account INNER JOIN contact ON account.accountid = contact.parentcustomerid";
 
@@ -160,7 +162,7 @@ public void Join()
         [TestMethod]
         public void JoinWithExtraCondition()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 SELECT
@@ -193,7 +195,7 @@ public void JoinWithExtraCondition()
         [TestMethod]
         public void NonUniqueJoin()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = "SELECT accountid, name FROM account INNER JOIN contact ON account.name = contact.fullname";
 
@@ -221,7 +223,7 @@ public void NonUniqueJoin()
         [TestMethod]
         public void NonUniqueJoinExpression()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = "SELECT accountid, name FROM account INNER JOIN contact ON account.name = (contact.firstname + ' ' + contact.lastname)";
 
@@ -258,7 +260,7 @@ public void NonUniqueJoinExpression()
         [TestMethod]
         public void SimpleWhere()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 SELECT
@@ -290,7 +292,7 @@ public void SimpleWhere()
         [TestMethod]
         public void WhereColumnComparison()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 SELECT
@@ -322,7 +324,7 @@ public void WhereColumnComparison()
         [TestMethod]
         public void WhereColumnComparisonCrossTable()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 SELECT
@@ -359,7 +361,7 @@ public void WhereColumnComparisonCrossTable()
         [TestMethod]
         public void SimpleSort()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 SELECT
@@ -389,7 +391,7 @@ ORDER BY
         [TestMethod]
         public void SimpleSortIndex()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 SELECT
@@ -419,7 +421,7 @@ ORDER BY
         [TestMethod]
         public void SimpleDistinct()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 SELECT DISTINCT
@@ -445,7 +447,7 @@ SELECT DISTINCT
         [TestMethod]
         public void SimpleTop()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 SELECT TOP 10
@@ -472,7 +474,7 @@ SELECT TOP 10
         [TestMethod]
         public void SimpleOffset()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 SELECT
@@ -502,7 +504,7 @@ ORDER BY name
         [TestMethod]
         public void SimpleGroupAggregate()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 SELECT
@@ -568,7 +570,7 @@ public void SimpleGroupAggregate()
         [TestMethod]
         public void AliasedAggregate()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 SELECT
@@ -618,7 +620,7 @@ public void AliasedAggregate()
         [TestMethod]
         public void AliasedGroupingAggregate()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 SELECT
@@ -668,7 +670,7 @@ public void AliasedGroupingAggregate()
         [TestMethod]
         public void SimpleAlias()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = "SELECT accountid, name AS test FROM account";
 
@@ -690,7 +692,7 @@ public void SimpleAlias()
         [TestMethod]
         public void SimpleHaving()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 SELECT
@@ -756,7 +758,7 @@ GROUP BY name
         [TestMethod]
         public void GroupByDatePart()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 SELECT
@@ -814,7 +816,7 @@ public void GroupByDatePart()
         [TestMethod]
         public void GroupByDatePartUsingYearMonthDayFunctions()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 SELECT
@@ -893,7 +895,7 @@ GROUP BY
         [TestMethod]
         public void PartialOrdering()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 SELECT
@@ -932,7 +934,7 @@ public void OrderByEntityName()
         {
             using (_localDataSource.SetOrderByEntityName(true))
             {
-                var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+                var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
                 var query = @"
                 SELECT TOP 1000
@@ -970,7 +972,7 @@ ORDER BY
         [TestMethod]
         public void PartialOrderingAvoidingLegacyPagingWithTop()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 SELECT TOP 100
@@ -1007,7 +1009,7 @@ ORDER BY
         [TestMethod]
         public void PartialWhere()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 SELECT
@@ -1043,7 +1045,7 @@ public void PartialWhere()
         [TestMethod]
         public void ComputeScalarSelect()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 SELECT firstname + ' ' + lastname AS fullname FROM contact WHERE firstname = 'Mark'";
@@ -1072,7 +1074,7 @@ public void ComputeScalarSelect()
         [TestMethod]
         public void ComputeScalarFilter()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 SELECT contactid FROM contact WHERE firstname + ' ' + lastname = 'Mark Carrington'";
@@ -1098,7 +1100,7 @@ public void ComputeScalarFilter()
         [TestMethod]
         public void SelectSubqueryWithMergeJoin()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 SELECT firstname + ' ' + lastname AS fullname, 'Account: ' + (SELECT name FROM account WHERE accountid = parentcustomerid) AS accountname FROM contact WHERE firstname = 'Mark'";
@@ -1131,7 +1133,7 @@ public void SelectSubqueryWithMergeJoin()
         [TestMethod]
         public void SelectSubqueryWithNestedLoop()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 SELECT firstname + ' ' + lastname AS fullname, 'Account: ' + (SELECT name FROM account WHERE createdon = contact.createdon) AS accountname FROM contact WHERE firstname = 'Mark'";
@@ -1181,7 +1183,7 @@ public void SelectSubqueryWithNestedLoop()
         [TestMethod]
         public void SelectSubqueryWithChildRecordUsesNestedLoop()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 SELECT name, (SELECT TOP 1 fullname FROM contact WHERE parentcustomerid = account.accountid) FROM account WHERE name = 'Data8'";
@@ -1224,7 +1226,7 @@ public void SelectSubqueryWithChildRecordUsesNestedLoop()
         [TestMethod]
         public void SelectSubqueryWithSmallNestedLoop()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 SELECT TOP 10 firstname + ' ' + lastname AS fullname, 'Account: ' + (SELECT name FROM account WHERE createdon = contact.createdon) AS accountname FROM contact WHERE firstname = 'Mark'";
@@ -1269,7 +1271,7 @@ public void SelectSubqueryWithSmallNestedLoop()
         [TestMethod]
         public void SelectSubqueryWithNonCorrelatedNestedLoop()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 SELECT firstname + ' ' + lastname AS fullname, 'Account: ' + (SELECT TOP 1 name FROM account) AS accountname FROM contact WHERE firstname = 'Mark'";
@@ -1311,7 +1313,7 @@ public void SelectSubqueryWithNonCorrelatedNestedLoop()
         [TestMethod]
         public void SelectSubqueryWithCorrelatedSpooledNestedLoop()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 SELECT firstname + ' ' + lastname AS fullname, 'Account: ' + (SELECT name FROM account WHERE createdon = contact.createdon) AS accountname FROM contact WHERE firstname = 'Mark'";
@@ -1362,7 +1364,7 @@ public void SelectSubqueryWithCorrelatedSpooledNestedLoop()
         [TestMethod]
         public void SelectSubqueryWithPartiallyCorrelatedSpooledNestedLoop()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 SELECT firstname + ' ' + lastname AS fullname, 'Account: ' + (SELECT name FROM account WHERE createdon = contact.createdon AND employees > 10) AS accountname FROM contact WHERE firstname = 'Mark'";
@@ -1415,7 +1417,7 @@ public void SelectSubqueryWithPartiallyCorrelatedSpooledNestedLoop()
         public void SelectSubqueryUsingOuterReferenceInSelectClause()
         {
             var tableSize = new StubTableSizeCache();
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 SELECT firstname + ' ' + lastname AS fullname, 'Account: ' + (SELECT firstname + ' ' + name FROM account WHERE accountid = parentcustomerid) AS accountname FROM contact WHERE firstname = 'Mark'";
@@ -1464,7 +1466,7 @@ public void SelectSubqueryUsingOuterReferenceInSelectClause()
         [TestMethod]
         public void SelectSubqueryUsingOuterReferenceInOrderByClause()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 SELECT firstname FROM contact ORDER BY (SELECT TOP 1 name FROM account WHERE accountid = parentcustomerid ORDER BY firstname)";
@@ -1504,7 +1506,7 @@ public void SelectSubqueryUsingOuterReferenceInOrderByClause()
         [TestMethod]
         public void WhereSubquery()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 SELECT firstname + ' ' + lastname AS fullname FROM contact WHERE (SELECT name FROM account WHERE accountid = parentcustomerid) = 'Data8'";
@@ -1535,7 +1537,7 @@ public void WhereSubquery()
         [TestMethod]
         public void ComputeScalarDistinct()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 SELECT DISTINCT TOP 10
@@ -1565,7 +1567,7 @@ SELECT DISTINCT TOP 10
         [TestMethod]
         public void Union()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 SELECT name FROM account
@@ -1608,7 +1610,7 @@ SELECT name FROM account
         [TestMethod]
         public void UnionMultiple()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 SELECT name FROM account
@@ -1662,7 +1664,7 @@ SELECT fullname FROM contact
         [TestMethod]
         public void UnionSort()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 SELECT name FROM account
@@ -1708,7 +1710,7 @@ SELECT fullname FROM contact
         [TestMethod]
         public void UnionSortOnAlias()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 SELECT name AS n FROM account
@@ -1754,7 +1756,7 @@ SELECT fullname FROM contact
         [TestMethod]
         public void UnionSortOnAliasedColumnsOriginalName()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 SELECT name AS n FROM account
@@ -1800,7 +1802,7 @@ SELECT fullname FROM contact
         [TestMethod]
         public void UnionAll()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 SELECT name FROM account
@@ -1839,7 +1841,7 @@ UNION ALL
         [TestMethod]
         public void SimpleInFilter()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 SELECT
@@ -1874,7 +1876,7 @@ public void SimpleInFilter()
         [TestMethod]
         public void SubqueryInFilterUncorrelated()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 SELECT
@@ -1915,7 +1917,7 @@ public void SubqueryInFilterUncorrelated()
         [ExpectedException(typeof(NotSupportedQueryFragmentException))]
         public void SubqueryInFilterMultipleColumnsError()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 SELECT
@@ -1932,7 +1934,7 @@ public void SubqueryInFilterMultipleColumnsError()
         [TestMethod]
         public void SubqueryInFilterUncorrelatedPrimaryKey()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 SELECT
@@ -1967,7 +1969,7 @@ public void SubqueryInFilterUncorrelatedPrimaryKey()
         [TestMethod]
         public void SubqueryInFilterCorrelated()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 SELECT
@@ -2015,7 +2017,7 @@ public void SubqueryInFilterCorrelated()
         [TestMethod]
         public void SubqueryNotInFilterCorrelated()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 SELECT
@@ -2063,7 +2065,7 @@ public void SubqueryNotInFilterCorrelated()
         [TestMethod]
         public void ExistsFilterUncorrelated()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 SELECT
@@ -2101,7 +2103,7 @@ public void ExistsFilterUncorrelated()
         [TestMethod]
         public void ExistsFilterCorrelatedPrimaryKey()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 SELECT
@@ -2133,7 +2135,7 @@ public void ExistsFilterCorrelatedPrimaryKey()
         [TestMethod]
         public void ExistsFilterCorrelatedPrimaryKeyOr()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 SELECT
@@ -2170,7 +2172,7 @@ public void ExistsFilterCorrelatedPrimaryKeyOr()
         [TestMethod]
         public void ExistsFilterCorrelated()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 SELECT
@@ -2216,7 +2218,7 @@ public void ExistsFilterCorrelatedWithAny()
         {
             using (_localDataSource.EnableJoinOperator(JoinOperator.Any))
             {
-                var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+                var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
                 var query = @"
                     SELECT
@@ -2255,7 +2257,7 @@ public void ExistsFilterCorrelatedWithAnyParentAndChildAndAdditionalFilter()
         {
             using (_localDataSource.EnableJoinOperator(JoinOperator.Any))
             {
-                var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+                var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
                 var query = @"
                     SELECT
@@ -2302,7 +2304,7 @@ public void NotExistsFilterCorrelatedOnLinkEntity()
         {
             using (_localDataSource.EnableJoinOperator(JoinOperator.NotAny))
             {
-                var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+                var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
                 var query = @"
                     SELECT
@@ -2342,7 +2344,7 @@ public void NotExistsFilterCorrelatedOnLinkEntity()
         [TestMethod]
         public void NotExistsFilterCorrelated()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 SELECT
@@ -2377,7 +2379,7 @@ public void NotExistsFilterCorrelated()
         [TestMethod]
         public void QueryDerivedTableSimple()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 SELECT TOP 10
@@ -2408,7 +2410,7 @@ SELECT TOP 10
         [TestMethod]
         public void QueryDerivedTableAlias()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 SELECT TOP 10
@@ -2439,7 +2441,7 @@ SELECT TOP 10
         [TestMethod]
         public void QueryDerivedTableValues()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 SELECT TOP 10
@@ -2458,7 +2460,7 @@ SELECT TOP 10
             var filter = AssertNode<FilterNode>(top.Source);
             var constant = AssertNode<ConstantScanNode>(filter.Source);
 
-            var schema = constant.GetSchema(new NodeCompilationContext(_dataSources, this, null, null));
+            var schema = constant.GetSchema(new NodeCompilationContext(new SessionContext(_localDataSources, this), this, null, null));
             Assert.AreEqual(typeof(SqlInt32), schema.Schema["a.ID"].Type.ToNetType(out _));
             Assert.AreEqual(typeof(SqlString), schema.Schema["a.name"].Type.ToNetType(out _));
         }
@@ -2466,7 +2468,7 @@ SELECT TOP 10
         [TestMethod]
         public void NoLockTableHint()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 SELECT TOP 10
@@ -2496,7 +2498,7 @@ SELECT TOP 10
         [TestMethod]
         public void CrossJoin()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 SELECT
@@ -2535,7 +2537,7 @@ CROSS JOIN
         [TestMethod]
         public void CrossApply()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 SELECT
@@ -2572,7 +2574,7 @@ FROM   contact
         [TestMethod]
         public void CrossApplyAllColumns()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 SELECT
@@ -2619,7 +2621,7 @@ FROM   contact
         [TestMethod]
         public void CrossApplyRestrictedColumns()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 SELECT
@@ -2656,7 +2658,7 @@ FROM   contact
         [TestMethod]
         public void CrossApplyRestrictedColumnsWithAlias()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 SELECT
@@ -2696,7 +2698,7 @@ FROM   contact
         [TestMethod]
         public void CrossApplyJoin()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 SELECT
@@ -2743,7 +2745,7 @@ FROM   contact
         [TestMethod]
         public void OuterApply()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 SELECT
@@ -2780,7 +2782,7 @@ FROM   contact
         [TestMethod]
         public void OuterApplyNestedLoop()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 SELECT
@@ -2838,7 +2840,7 @@ ORDER BY firstname
         [TestMethod]
         public void FetchXmlNativeWhere()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 SELECT
@@ -2870,7 +2872,7 @@ public void FetchXmlNativeWhere()
         [TestMethod]
         public void SimpleMetadataSelect()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 SELECT logicalname
@@ -2891,7 +2893,7 @@ SELECT logicalname
         [TestMethod]
         public void SimpleMetadataWhere()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 SELECT logicalname
@@ -2917,7 +2919,7 @@ FROM   metadata.entity
         [TestMethod]
         public void CaseSensitiveMetadataWhere()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 SELECT logicalname
@@ -2948,7 +2950,7 @@ FROM   metadata.entity
         [TestMethod]
         public void SimpleUpdate()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = "UPDATE account SET name = 'foo' WHERE name = 'bar'";
 
@@ -2977,7 +2979,7 @@ public void SimpleUpdate()
         [TestMethod]
         public void UpdateFromJoin()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = "UPDATE a SET name = 'foo' FROM account a INNER JOIN contact c ON a.accountid = c.parentcustomerid WHERE name = 'bar'";
 
@@ -3009,7 +3011,7 @@ public void UpdateFromJoin()
         [TestMethod]
         public void QueryHints()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = "SELECT accountid, name FROM account OPTION (OPTIMIZE FOR UNKNOWN, FORCE ORDER, RECOMPILE, USE HINT('DISABLE_OPTIMIZER_ROWGOAL'), USE HINT('ENABLE_QUERY_OPTIMIZER_HOTFIXES'), LOOP JOIN, MERGE JOIN, HASH JOIN, NO_PERFORMANCE_SPOOL, MAXRECURSION 2)";
 
@@ -3031,7 +3033,7 @@ public void QueryHints()
         [TestMethod]
         public void AggregateSort()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = "SELECT name, count(*) from account group by name order by 2 desc";
 
@@ -3083,7 +3085,7 @@ public void AggregateSort()
         [TestMethod]
         public void FoldFilterWithNonFoldedJoin()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = "SELECT name from account INNER JOIN contact ON left(name, 4) = left(firstname, 4) where name like 'Data8%' and firstname like 'Mark%'";
 
@@ -3124,7 +3126,7 @@ public void FoldFilterWithNonFoldedJoin()
         [TestMethod]
         public void FoldFilterWithInClause()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = "SELECT name from account where name like 'Data8%' and primarycontactid in (select contactid from contact where firstname = 'Mark')";
 
@@ -3153,7 +3155,7 @@ public void FoldFilterWithInClause()
         [TestMethod]
         public void FoldFilterWithInClauseOr()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = "SELECT name from account where name like 'Data8%' or primarycontactid in (select contactid from contact where firstname = 'Mark')";
 
@@ -3185,7 +3187,7 @@ public void FoldFilterWithInClauseWithoutPrimaryKey()
         {
             using (_localDataSource.EnableJoinOperator(JoinOperator.In))
             {
-                var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+                var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
                 var query = "SELECT name from account where name like 'Data8%' and createdon in (select createdon from contact where firstname = 'Mark')";
 
@@ -3215,7 +3217,7 @@ public void FoldFilterWithInClauseWithoutPrimaryKey()
         [TestMethod]
         public void FoldNotInToLeftOuterJoin()
         {
-            var planBuilder = new ExecutionPlanBuilder(_dataSources.Values, new OptionsWrapper(this) { PrimaryDataSource = "uat" });
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_dataSources, new OptionsWrapper(this) { PrimaryDataSource = "uat" }), new OptionsWrapper(this) { PrimaryDataSource = "uat" });
 
             var query = "SELECT name from account where name like 'Data8%' and createdon not in (select createdon from contact where firstname = 'Mark')";
 
@@ -3248,7 +3250,7 @@ public void FoldFilterWithInClauseOnLinkEntityWithoutPrimaryKey()
         {
             using (_localDataSource.EnableJoinOperator(JoinOperator.In))
             {
-                var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+                var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
                 var query = "SELECT name from account inner join contact on account.accountid = contact.parentcustomerid where name like 'Data8%' and contact.createdon in (select createdon from contact where firstname = 'Mark')";
 
@@ -3282,7 +3284,7 @@ public void FoldFilterWithExistsClauseWithoutPrimaryKey()
         {
             using (_localDataSource.EnableJoinOperator(JoinOperator.Exists))
             {
-                var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+                var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
                 var query = "SELECT name from account where name like 'Data8%' and exists (select * from contact where firstname = 'Mark' and createdon = account.createdon)";
 
@@ -3313,7 +3315,7 @@ public void FoldFilterWithExistsClauseWithoutPrimaryKey()
         [TestMethod]
         public void DistinctNotRequiredWithPrimaryKey()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = "SELECT DISTINCT accountid, name from account";
 
@@ -3335,7 +3337,7 @@ public void DistinctNotRequiredWithPrimaryKey()
         [TestMethod]
         public void DistinctRequiredWithoutPrimaryKey()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = "SELECT DISTINCT accountid, name from account INNER JOIN contact ON account.accountid = contact.parentcustomerid";
 
@@ -3361,7 +3363,7 @@ public void DistinctRequiredWithoutPrimaryKey()
         [TestMethod]
         public void SimpleDelete()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = "DELETE FROM account WHERE name = 'bar'";
 
@@ -3387,7 +3389,7 @@ public void SimpleDelete()
         [TestMethod]
         public void SimpleInsertSelect()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = "INSERT INTO account (name) SELECT fullname FROM contact WHERE firstname = 'Mark'";
 
@@ -3413,7 +3415,7 @@ public void SimpleInsertSelect()
         [TestMethod]
         public void SelectDuplicateColumnNames()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = "SELECT fullname, lastname + ', ' + firstname as fullname FROM contact WHERE firstname = 'Mark'";
 
@@ -3446,7 +3448,7 @@ public void SelectDuplicateColumnNames()
         [ExpectedException(typeof(NotSupportedQueryFragmentException))]
         public void SubQueryDuplicateColumnNamesError()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = "SELECT * FROM (SELECT fullname, lastname + ', ' + firstname as fullname FROM contact WHERE firstname = 'Mark') a";
 
@@ -3456,7 +3458,7 @@ public void SubQueryDuplicateColumnNamesError()
         [TestMethod]
         public void UnionDuplicateColumnNames()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"SELECT fullname, lastname + ', ' + firstname as fullname FROM contact WHERE firstname = 'Mark'
                           UNION
@@ -3487,7 +3489,7 @@ public void UnionDuplicateColumnNames()
         [ExpectedException(typeof(NotSupportedQueryFragmentException))]
         public void SubQueryUnionDuplicateColumnNamesError()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
             var query = @"SELECT * FROM (
                             SELECT fullname, lastname + ', ' + firstname as fullname FROM contact WHERE firstname = 'Mark'
                             UNION
@@ -3523,7 +3525,7 @@ private void AssertFetchXml(FetchXmlScan node, string fetchXml)
         [TestMethod]
         public void SelectStarInSubquery()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"SELECT * FROM account WHERE accountid IN (SELECT parentcustomerid FROM contact)";
 
@@ -3563,7 +3565,7 @@ public void SelectStarInSubquery()
         [ExpectedException(typeof(NotSupportedQueryFragmentException))]
         public void CannotSelectColumnsFromSemiJoin()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"SELECT contact.* FROM account WHERE accountid IN (SELECT parentcustomerid FROM contact)";
 
@@ -3573,7 +3575,7 @@ public void CannotSelectColumnsFromSemiJoin()
         [TestMethod]
         public void MinAggregateNotFoldedToFetchXmlForOptionset()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"SELECT new_name, min(new_optionsetvalue) FROM new_customentity GROUP BY new_name";
 
@@ -3598,7 +3600,7 @@ public void MinAggregateNotFoldedToFetchXmlForOptionset()
         [TestMethod]
         public void HelpfulErrorMessageOnMissingGroupBy()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"SELECT new_name, min(new_optionsetvalue) FROM new_customentity";
 
@@ -3616,7 +3618,7 @@ public void HelpfulErrorMessageOnMissingGroupBy()
         [TestMethod]
         public void AggregateInSubquery()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"SELECT firstname
                           FROM   contact
@@ -3712,7 +3714,7 @@ GROUP BY firstname
                 },
             };
             
-            var result = select.Execute(new NodeExecutionContext(_localDataSources, this, new Dictionary<string, DataTypeReference>(), new Dictionary<string, INullable>(), null), CommandBehavior.Default);
+            var result = select.Execute(new NodeExecutionContext(new SessionContext(_localDataSources, this), this, new Dictionary<string, DataTypeReference>(), new Dictionary<string, INullable>(), null), CommandBehavior.Default);
             var dataTable = new DataTable();
             dataTable.Load(result);
 
@@ -3724,7 +3726,7 @@ GROUP BY firstname
         [TestMethod]
         public void SelectVirtualNameAttributeFromLinkEntity()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = "SELECT parentcustomeridname FROM account INNER JOIN contact ON account.accountid = contact.parentcustomerid";
 
@@ -3747,7 +3749,7 @@ public void SelectVirtualNameAttributeFromLinkEntity()
         [TestMethod]
         public void DuplicatedDistinctColumns()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = "SELECT DISTINCT name AS n1, name AS n2 FROM account";
 
@@ -3769,7 +3771,7 @@ public void DuplicatedDistinctColumns()
         [TestMethod]
         public void GroupByDatetimeWithoutDatePart()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = "SELECT createdon, COUNT(*) FROM account GROUP BY createdon";
 
@@ -3792,7 +3794,7 @@ public void GroupByDatetimeWithoutDatePart()
         [TestMethod]
         public void MetadataExpressions()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = "SELECT collectionschemaname + '.' + entitysetname FROM metadata.entity WHERE description LIKE '%test%'";
 
@@ -3817,7 +3819,7 @@ public void MetadataExpressions()
         [TestMethod]
         public void AliasedAttribute()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = "SELECT name AS n1 FROM account WHERE name = 'test'";
 
@@ -3844,7 +3846,7 @@ public void AliasedAttribute()
         [TestMethod]
         public void MultipleAliases()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = "SELECT name AS n1, name AS n2 FROM account WHERE name = 'test'";
 
@@ -3898,10 +3900,14 @@ public void CrossInstanceJoin()
                 new DataSource
                 {
                     Name = "local", // Hack so that ((IQueryExecutionOptions)this).PrimaryDataSource = "local" doesn't cause test to fail
+                    Connection = _context2.GetOrganizationService(),
+                    Metadata = metadata2,
+                    TableSizeCache = new StubTableSizeCache(),
+                    MessageCache = new StubMessageCache(),
                     DefaultCollation = Collation.USEnglish
                 }
             };
-            var planBuilder = new ExecutionPlanBuilder(datasources, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(datasources.ToDictionary(d => d.Name), this), this);
 
             var query = "SELECT uat.name, prod.name FROM uat.dbo.account AS uat INNER JOIN prod.dbo.account AS prod ON uat.accountid = prod.accountid WHERE uat.name <> prod.name AND uat.name LIKE '%test%'";
 
@@ -3947,7 +3953,7 @@ public void CrossInstanceJoin()
         [TestMethod]
         public void FilterOnGroupByExpression()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
             SELECT
@@ -3991,7 +3997,7 @@ GROUP BY
         [TestMethod]
         public void SystemFunctions()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = "SELECT CURRENT_TIMESTAMP, CURRENT_USER, GETDATE(), USER_NAME()";
 
@@ -4007,7 +4013,7 @@ public void SystemFunctions()
         [TestMethod]
         public void FoldEqualsCurrentUser()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = "SELECT name FROM account WHERE ownerid = CURRENT_USER";
 
@@ -4031,7 +4037,7 @@ public void FoldEqualsCurrentUser()
         [TestMethod]
         public void DoNotFoldEqualsCurrentUserOnStringField()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = "SELECT systemuserid FROM systemuser WHERE domainname = CURRENT_USER";
 
@@ -4061,7 +4067,7 @@ public void DoNotFoldEqualsCurrentUserOnStringField()
         [TestMethod]
         public void UseNestedLoopToInjectDynamicFilterValue_GlobalVariable()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = "SELECT * FROM account WHERE turnover = CAST(CURRENT_TIMESTAMP AS int)";
 
@@ -4091,7 +4097,7 @@ public void UseNestedLoopToInjectDynamicFilterValue_GlobalVariable()
         [TestMethod]
         public void UseNestedLoopToInjectDynamicFilterValue_NonDeterministicFunction()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = "SELECT * FROM account WHERE turnover = CAST(GETDATE() AS int)";
 
@@ -4121,7 +4127,7 @@ public void UseNestedLoopToInjectDynamicFilterValue_NonDeterministicFunction()
         [TestMethod]
         public void DoNotUseNestedLoopToInjectDynamicFilterValue_DeterministicFunction()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = "SELECT * FROM account WHERE turnover = CAST(LEFT('1test', 1) AS int) + 1";
 
@@ -4145,7 +4151,7 @@ public void DoNotUseNestedLoopToInjectDynamicFilterValue_DeterministicFunction()
         [TestMethod]
         public void EntityReferenceInQuery()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = "SELECT name FROM account WHERE accountid IN ('0000000000000000-0000-0000-000000000000', '0000000000000000-0000-0000-000000000001')";
 
@@ -4172,7 +4178,7 @@ public void EntityReferenceInQuery()
         [TestMethod]
         public void OrderBySelectExpression()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = "SELECT name + 'foo' FROM account ORDER BY 1";
 
@@ -4198,7 +4204,7 @@ public void OrderBySelectExpression()
         [TestMethod]
         public void OrderByAlias()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = "SELECT name AS companyname FROM account ORDER BY companyname";
 
@@ -4223,7 +4229,7 @@ public void OrderByAlias()
         [ExpectedException(typeof(NotSupportedQueryFragmentException))]
         public void OrderByAliasCantUseExpression()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = "SELECT name AS companyname FROM account ORDER BY companyname + ''";
 
@@ -4233,7 +4239,7 @@ public void OrderByAliasCantUseExpression()
         [TestMethod]
         public void DistinctOrderByUsesScalarAggregate()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = "SELECT DISTINCT account.accountid FROM metadata.entity INNER JOIN account ON entity.metadataid = account.accountid";
 
@@ -4263,7 +4269,7 @@ public void DistinctOrderByUsesScalarAggregate()
         [ExpectedException(typeof(NotSupportedQueryFragmentException))]
         public void WindowFunctionsNotSupported()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = "SELECT COUNT(accountid) OVER(PARTITION BY accountid) AS test FROM account";
 
@@ -4273,7 +4279,7 @@ public void WindowFunctionsNotSupported()
         [TestMethod]
         public void DeclareVariableSetLiteralSelect()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 DECLARE @test int
@@ -4310,7 +4316,7 @@ DECLARE @test int
             {
                 if (plan is IDataReaderExecutionPlanNode selectQuery)
                 {
-                    var results = selectQuery.Execute(new NodeExecutionContext(_dataSources, this, parameterTypes, parameterValues, null), CommandBehavior.Default);
+                    var results = selectQuery.Execute(new NodeExecutionContext(new SessionContext(_localDataSources, this), this, parameterTypes, parameterValues, null), CommandBehavior.Default);
                     var dataTable = new DataTable();
                     dataTable.Load(results);
 
@@ -4320,7 +4326,7 @@ DECLARE @test int
                 }
                 else if (plan is IDmlQueryExecutionPlanNode dmlQuery)
                 {
-                    dmlQuery.Execute(new NodeExecutionContext(_dataSources, this, parameterTypes, parameterValues, null), out _, out _);
+                    dmlQuery.Execute(new NodeExecutionContext(new SessionContext(_localDataSources, this), this, parameterTypes, parameterValues, null), out _, out _);
                 }
             }
         }
@@ -4328,7 +4334,7 @@ DECLARE @test int
         [TestMethod]
         public void SetVariableInDeclaration()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 DECLARE @test int = 1
@@ -4364,7 +4370,7 @@ public void SetVariableInDeclaration()
             {
                 if (plan is IDataReaderExecutionPlanNode selectQuery)
                 {
-                    var results = selectQuery.Execute(new NodeExecutionContext(_dataSources, this, parameterTypes, parameterValues, null), CommandBehavior.Default);
+                    var results = selectQuery.Execute(new NodeExecutionContext(new SessionContext(_localDataSources, this), this, parameterTypes, parameterValues, null), CommandBehavior.Default);
                     var dataTable = new DataTable();
                     dataTable.Load(results);
 
@@ -4374,7 +4380,7 @@ public void SetVariableInDeclaration()
                 }
                 else if (plan is IDmlQueryExecutionPlanNode dmlQuery)
                 {
-                    dmlQuery.Execute(new NodeExecutionContext(_dataSources, this, parameterTypes, parameterValues, null), out _, out _);
+                    dmlQuery.Execute(new NodeExecutionContext(new SessionContext(_localDataSources, this), this, parameterTypes, parameterValues, null), out _, out _);
                 }
             }
         }
@@ -4383,7 +4389,7 @@ public void SetVariableInDeclaration()
         [ExpectedException(typeof(NotSupportedQueryFragmentException))]
         public void UnknownVariable()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = "SET @test = 1";
 
@@ -4394,7 +4400,7 @@ public void UnknownVariable()
         [ExpectedException(typeof(NotSupportedQueryFragmentException))]
         public void DuplicateVariable()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 DECLARE @test INT
@@ -4406,7 +4412,7 @@ DECLARE @test INT
         [TestMethod]
         public void VariableTypeConversionIntToString()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 DECLARE @test varchar(3)
@@ -4422,7 +4428,7 @@ DECLARE @test varchar(3)
             {
                 if (plan is IDataReaderExecutionPlanNode selectQuery)
                 {
-                    var results = selectQuery.Execute(new NodeExecutionContext(_localDataSources, this, parameterTypes, parameterValues, null), CommandBehavior.Default);
+                    var results = selectQuery.Execute(new NodeExecutionContext(new SessionContext(_localDataSources, this), this, parameterTypes, parameterValues, null), CommandBehavior.Default);
                     var dataTable = new DataTable();
                     dataTable.Load(results);
 
@@ -4432,7 +4438,7 @@ DECLARE @test varchar(3)
                 }
                 else if (plan is IDmlQueryExecutionPlanNode dmlQuery)
                 {
-                    dmlQuery.Execute(new NodeExecutionContext(_localDataSources, this, parameterTypes, parameterValues, null), out _, out _);
+                    dmlQuery.Execute(new NodeExecutionContext(new SessionContext(_localDataSources, this), this, parameterTypes, parameterValues, null), out _, out _);
                 }
             }
         }
@@ -4440,7 +4446,7 @@ DECLARE @test varchar(3)
         [TestMethod]
         public void VariableTypeConversionStringTruncation()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 DECLARE @test varchar(3)
@@ -4456,7 +4462,7 @@ DECLARE @test varchar(3)
             {
                 if (plan is IDataReaderExecutionPlanNode selectQuery)
                 {
-                    var results = selectQuery.Execute(new NodeExecutionContext(_localDataSources, this, parameterTypes, parameterValues, null), CommandBehavior.Default);
+                    var results = selectQuery.Execute(new NodeExecutionContext(new SessionContext(_localDataSources, this), this, parameterTypes, parameterValues, null), CommandBehavior.Default);
                     var dataTable = new DataTable();
                     dataTable.Load(results);
 
@@ -4466,7 +4472,7 @@ DECLARE @test varchar(3)
                 }
                 else if (plan is IDmlQueryExecutionPlanNode dmlQuery)
                 {
-                    dmlQuery.Execute(new NodeExecutionContext(_localDataSources, this, parameterTypes, parameterValues, null), out _, out _);
+                    dmlQuery.Execute(new NodeExecutionContext(new SessionContext(_localDataSources, this), this, parameterTypes, parameterValues, null), out _, out _);
                 }
             }
         }
@@ -4475,7 +4481,7 @@ DECLARE @test varchar(3)
         [ExpectedException(typeof(NotSupportedQueryFragmentException))]
         public void CannotCombineSetVariableAndDataRetrievalInSelect()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             // A SELECT statement that assigns a value to a variable must not be combined with data-retrieval operations
             var query = @"
@@ -4488,7 +4494,7 @@ DECLARE @test varchar(3)
         [TestMethod]
         public void SetVariableWithSelectUsesFinalValue()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 DECLARE @test varchar(3)
@@ -4548,7 +4554,7 @@ DECLARE @test varchar(3)
             {
                 if (plan is IDataReaderExecutionPlanNode selectQuery)
                 {
-                    var results = selectQuery.Execute(new NodeExecutionContext(_localDataSources, this, parameterTypes, parameterValues, null), CommandBehavior.Default);
+                    var results = selectQuery.Execute(new NodeExecutionContext(new SessionContext(_localDataSources, this), this, parameterTypes, parameterValues, null), CommandBehavior.Default);
                     var dataTable = new DataTable();
                     dataTable.Load(results);
 
@@ -4558,7 +4564,7 @@ DECLARE @test varchar(3)
                 }
                 else if (plan is IDmlQueryExecutionPlanNode dmlQuery)
                 {
-                    dmlQuery.Execute(new NodeExecutionContext(_localDataSources, this, parameterTypes, parameterValues, null), out _, out _);
+                    dmlQuery.Execute(new NodeExecutionContext(new SessionContext(_localDataSources, this), this, parameterTypes, parameterValues, null), out _, out _);
                 }
             }
         }
@@ -4566,7 +4572,7 @@ DECLARE @test varchar(3)
         [TestMethod]
         public void VarCharLengthDefaultsTo1()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 DECLARE @test varchar
@@ -4582,7 +4588,7 @@ DECLARE @test varchar
             {
                 if (plan is IDataReaderExecutionPlanNode selectQuery)
                 {
-                    var results = selectQuery.Execute(new NodeExecutionContext(_localDataSources, this, parameterTypes, parameterValues, null), CommandBehavior.Default);
+                    var results = selectQuery.Execute(new NodeExecutionContext(new SessionContext(_localDataSources, this), this, parameterTypes, parameterValues, null), CommandBehavior.Default);
                     var dataTable = new DataTable();
                     dataTable.Load(results);
 
@@ -4592,7 +4598,7 @@ DECLARE @test varchar
                 }
                 else if (plan is IDmlQueryExecutionPlanNode dmlQuery)
                 {
-                    dmlQuery.Execute(new NodeExecutionContext(_localDataSources, this, parameterTypes, parameterValues, null), out _, out _);
+                    dmlQuery.Execute(new NodeExecutionContext(new SessionContext(_localDataSources, this), this, parameterTypes, parameterValues, null), out _, out _);
                 }
             }
         }
@@ -4601,7 +4607,7 @@ DECLARE @test varchar
         [ExpectedException(typeof(NotSupportedQueryFragmentException))]
         public void CursorVariableNotSupported()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 DECLARE @test CURSOR";
@@ -4613,7 +4619,7 @@ public void CursorVariableNotSupported()
         [ExpectedException(typeof(NotSupportedQueryFragmentException))]
         public void TableVariableNotSupported()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 DECLARE @test TABLE (ID INT)";
@@ -4624,7 +4630,7 @@ public void TableVariableNotSupported()
         [TestMethod]
         public void IfStatement()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this) { EstimatedPlanOnly = true };
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this) { EstimatedPlanOnly = true };
 
             var query = @"
                 IF @param1 = 1
@@ -4658,7 +4664,7 @@ INSERT INTO account (name) VALUES ('one')
         [TestMethod]
         public void WhileStatement()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this) { EstimatedPlanOnly = true };
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this) { EstimatedPlanOnly = true };
 
             var query = @"
                 WHILE @param1 < 10
@@ -4687,7 +4693,7 @@ INSERT INTO account (name) VALUES (@param1)
         [TestMethod]
         public void IfNotExists()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this) { EstimatedPlanOnly = true };
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this) { EstimatedPlanOnly = true };
 
             var query = @"
                 IF NOT EXISTS(SELECT * FROM account WHERE name = @param1)
@@ -4712,7 +4718,7 @@ INSERT INTO account (name) VALUES (@param1)
         [TestMethod]
         public void DuplicatedAliases()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = "SELECT name, createdon AS name FROM account";
 
@@ -4734,7 +4740,7 @@ public void DuplicatedAliases()
         [TestMethod]
         public void MetadataLeftJoinData()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 SELECT entity.logicalname, account.name, contact.firstname 
@@ -4773,7 +4779,7 @@ public void MetadataLeftJoinData()
         [TestMethod]
         public void NotEqualExcludesNull()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 SELECT name FROM account WHERE name <> 'Data8'";
@@ -4799,7 +4805,7 @@ public void NotEqualExcludesNull()
         [TestMethod]
         public void DistinctFromAllowsNull()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 SELECT name FROM account WHERE name IS DISTINCT FROM 'Data8'";
@@ -4824,7 +4830,7 @@ public void DistinctFromAllowsNull()
         [TestMethod]
         public void DoNotFoldFilterOnNameVirtualAttributeWithTooManyJoins()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 select top 10 a.name
@@ -4917,7 +4923,7 @@ from account a
         [TestMethod]
         public void FilterOnVirtualTypeAttributeEquals()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"SELECT firstname FROM contact WHERE parentcustomeridtype = 'contact'";
 
@@ -4941,7 +4947,7 @@ public void FilterOnVirtualTypeAttributeEquals()
         [TestMethod]
         public void FilterOnVirtualTypeAttributeEqualsImpossible()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"SELECT firstname FROM contact WHERE parentcustomeridtype = 'non-existent-entity'";
 
@@ -4965,7 +4971,7 @@ public void FilterOnVirtualTypeAttributeEqualsImpossible()
         [TestMethod]
         public void FilterOnVirtualTypeAttributeNotEquals()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"SELECT firstname FROM contact WHERE parentcustomeridtype <> 'contact'";
 
@@ -4990,7 +4996,7 @@ public void FilterOnVirtualTypeAttributeNotEquals()
         [TestMethod]
         public void FilterOnVirtualTypeAttributeNotInImpossible()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"SELECT firstname FROM contact WHERE parentcustomeridtype NOT IN ('account', 'contact')";
 
@@ -5017,7 +5023,7 @@ public void FilterOnVirtualTypeAttributeNotInImpossible()
         [TestMethod]
         public void FilterOnVirtualTypeAttributeNull()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"SELECT firstname FROM contact WHERE parentcustomeridtype IS NULL";
 
@@ -5041,7 +5047,7 @@ public void FilterOnVirtualTypeAttributeNull()
         [TestMethod]
         public void FilterOnVirtualTypeAttributeNotNull()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"SELECT firstname FROM contact WHERE parentcustomeridtype IS NOT NULL";
 
@@ -5065,7 +5071,7 @@ public void FilterOnVirtualTypeAttributeNotNull()
         [TestMethod]
         public void SubqueriesInValueList()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"SELECT a FROM (VALUES ('a'), ((SELECT TOP 1 firstname FROM contact)), ('b'), (1)) AS MyTable (a)";
 
@@ -5094,7 +5100,7 @@ public void SubqueriesInValueList()
         [TestMethod]
         public void FoldFilterOnIdentity()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"SELECT name FROM account WHERE accountid = @@IDENTITY";
 
@@ -5119,7 +5125,7 @@ public void FoldFilterOnIdentity()
         [TestMethod]
         public void FoldPrimaryIdInQuery()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"SELECT name FROM account WHERE accountid IN (SELECT accountid FROM account INNER JOIN contact ON account.primarycontactid = contact.contactid WHERE name = 'Data8')";
 
@@ -5145,7 +5151,7 @@ public void FoldPrimaryIdInQuery()
         [TestMethod]
         public void FoldPrimaryIdInQueryWithTop()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"DELETE FROM account WHERE accountid IN (SELECT TOP 10 accountid FROM account ORDER BY createdon DESC)";
 
@@ -5168,7 +5174,7 @@ public void FoldPrimaryIdInQueryWithTop()
         [TestMethod]
         public void InsertParameters()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"DECLARE @name varchar(100) = 'test'; INSERT INTO account (name) VALUES (@name)";
 
@@ -5186,7 +5192,7 @@ public void InsertParameters()
         [TestMethod]
         public void NotExistsParameters()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"DECLARE @firstname AS VARCHAR (100) = 'Mark', @lastname AS VARCHAR (100) = 'Carrington';
 
@@ -5227,7 +5233,7 @@ INSERT INTO contact (firstname, lastname)
         [TestMethod]
         public void UpdateParameters()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"declare @name varchar(100) = 'Data8', @employees int = 10
 UPDATE account SET employees = @employees WHERE name = @name";
@@ -5258,7 +5264,7 @@ public void UpdateParameters()
         [TestMethod]
         public void CountUsesAggregateByDefault()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"SELECT count(*) FROM account";
 
@@ -5282,7 +5288,7 @@ public void CountUsesAggregateByDefault()
         [TestMethod]
         public void CountUsesRetrieveTotalRecordCountWithHint()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"SELECT count(*) FROM account OPTION (USE HINT ('RETRIEVE_TOTAL_RECORD_COUNT'))";
 
@@ -5301,7 +5307,7 @@ public void CountUsesRetrieveTotalRecordCountWithHint()
         [TestMethod]
         public void MaxDOPUsesDefault()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"UPDATE account SET name = 'test'";
 
@@ -5316,7 +5322,7 @@ public void MaxDOPUsesDefault()
         [TestMethod]
         public void MaxDOPUsesHint()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"UPDATE account SET name = 'test' OPTION (MAXDOP 7)";
 
@@ -5331,7 +5337,7 @@ public void MaxDOPUsesHint()
         [TestMethod]
         public void MaxDOPUsesHintInsideIfBlock()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"IF (1 = 1) BEGIN UPDATE account SET name = 'test' OPTION (MAXDOP 7) END";
 
@@ -5347,7 +5353,7 @@ public void MaxDOPUsesHintInsideIfBlock()
         [TestMethod]
         public void SubqueryUsesSpoolByDefault()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"SELECT accountid, (SELECT TOP 1 fullname FROM contact) FROM account";
 
@@ -5365,7 +5371,7 @@ public void SubqueryUsesSpoolByDefault()
         [TestMethod]
         public void SubqueryDoesntUseSpoolWithHint()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"SELECT accountid, (SELECT TOP 1 fullname FROM contact) FROM account OPTION (NO_PERFORMANCE_SPOOL)";
 
@@ -5382,7 +5388,7 @@ public void SubqueryDoesntUseSpoolWithHint()
         [TestMethod]
         public void BypassPluginExecutionUsesDefault()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"UPDATE account SET name = 'test'";
 
@@ -5397,7 +5403,7 @@ public void BypassPluginExecutionUsesDefault()
         [TestMethod]
         public void BypassPluginExecutionUsesHint()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"UPDATE account SET name = 'test' OPTION (USE HINT ('BYPASS_CUSTOM_PLUGIN_EXECUTION'))";
 
@@ -5412,7 +5418,7 @@ public void BypassPluginExecutionUsesHint()
         [TestMethod]
         public void PageSizeUsesHint()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"SELECT name FROM account OPTION (USE HINT ('FETCHXML_PAGE_SIZE_100'))";
 
@@ -5434,7 +5440,7 @@ public void PageSizeUsesHint()
         [TestMethod]
         public void DistinctOrderByOptionSet()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = "SELECT DISTINCT new_optionsetvalue FROM new_customentity ORDER BY new_optionsetvalue";
 
@@ -5457,7 +5463,7 @@ public void DistinctOrderByOptionSet()
         [TestMethod]
         public void DistinctVirtualAttribute()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = "SELECT DISTINCT new_optionsetvaluename FROM new_customentity";
 
@@ -5482,7 +5488,7 @@ public void DistinctVirtualAttribute()
         [TestMethod]
         public void TopAliasStar()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = "SELECT TOP 10 A.* FROM account A";
 
@@ -5503,7 +5509,7 @@ public void TopAliasStar()
         [TestMethod]
         public void OrderByStar()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = "SELECT * FROM account ORDER BY primarycontactid";
 
@@ -5525,7 +5531,7 @@ public void OrderByStar()
         [TestMethod]
         public void UpdateColumnInWhereClause()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = "UPDATE account SET name = '1' WHERE name <> '1'";
 
@@ -5555,7 +5561,7 @@ public void UpdateColumnInWhereClause()
         [TestMethod]
         public void NestedOrFilters()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = "SELECT * FROM account WHERE name = '1' OR name = '2' OR name = '3' OR name = '4'";
 
@@ -5583,7 +5589,7 @@ public void NestedOrFilters()
         [TestMethod]
         public void UnknownHint()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = "SELECT * FROM account OPTION(USE HINT('invalid'))";
 
@@ -5593,7 +5599,7 @@ public void UnknownHint()
         [TestMethod]
         public void MultipleTablesJoinFromWhereClause()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = "SELECT firstname FROM account, contact WHERE accountid = parentcustomerid AND lastname = 'Carrington' AND name = 'Data8'";
 
@@ -5622,7 +5628,7 @@ public void MultipleTablesJoinFromWhereClause()
         [TestMethod]
         public void MultipleTablesJoinFromWhereClauseReversed()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = "SELECT firstname FROM account, contact WHERE lastname = 'Carrington' AND name = 'Data8' AND parentcustomerid = accountid";
 
@@ -5651,7 +5657,7 @@ public void MultipleTablesJoinFromWhereClauseReversed()
         [TestMethod]
         public void MultipleTablesJoinFromWhereClause3()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = "SELECT firstname FROM account, contact, systemuser WHERE accountid = parentcustomerid AND lastname = 'Carrington' AND name = 'Data8' AND account.ownerid = systemuserid";
 
@@ -5681,7 +5687,7 @@ public void MultipleTablesJoinFromWhereClause3()
         [TestMethod]
         public void NestedInSubqueries()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = "SELECT firstname FROM contact WHERE parentcustomerid IN (SELECT accountid FROM account WHERE primarycontactid IN (SELECT contactid FROM contact WHERE lastname = 'Carrington'))";
 
@@ -5709,7 +5715,7 @@ public void NestedInSubqueries()
         [TestMethod]
         public void SpoolNestedLoop()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = "SELECT account.name, contact.fullname FROM account INNER JOIN contact ON account.accountid = contact.parentcustomerid OR account.createdon < contact.createdon";
 
@@ -5744,7 +5750,7 @@ public void SpoolNestedLoop()
         [TestMethod]
         public void SelectFromTVF()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = "SELECT * FROM SampleMessage('test')";
 
@@ -5763,7 +5769,7 @@ public void SelectFromTVF()
         [TestMethod]
         public void OuterApplyCorrelatedTVF()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = "SELECT account.name, msg.OutputParam1 FROM account OUTER APPLY (SELECT * FROM SampleMessage(account.name)) AS msg WHERE account.name = 'Data8'";
 
@@ -5790,7 +5796,7 @@ public void OuterApplyCorrelatedTVF()
         [TestMethod]
         public void OuterApplyUncorrelatedTVF()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = "SELECT account.name, msg.OutputParam1 FROM account OUTER APPLY (SELECT * FROM SampleMessage('test')) AS msg WHERE account.name = 'Data8'";
 
@@ -5817,7 +5823,7 @@ public void OuterApplyUncorrelatedTVF()
         [TestMethod]
         public void TVFScalarSubqueryParameter()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = "SELECT * FROM SampleMessage((SELECT TOP 1 name FROM account))";
 
@@ -5858,7 +5864,7 @@ public void TVFScalarSubqueryParameter()
         [TestMethod]
         public void ExecuteSproc()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = "EXEC SampleMessage 'test'";
 
@@ -5875,7 +5881,7 @@ public void ExecuteSproc()
         [TestMethod]
         public void ExecuteSprocNamedParameters()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"DECLARE @i int
                 EXEC SampleMessage @StringParam = 'test', @OutputParam2 = @i OUTPUT
@@ -5895,7 +5901,7 @@ public void FoldMultipleJoinConditionsWithKnownValue()
         {
             using (_localDataSource.SetColumnComparison(false))
             {
-                var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+                var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
                 var query = @"SELECT a.name, c.fullname FROM account a INNER JOIN contact c ON a.accountid = c.parentcustomerid AND a.name = c.fullname WHERE a.name = 'Data8'";
 
@@ -5926,7 +5932,7 @@ public void FoldMultipleJoinConditionsWithKnownValue()
         [ExpectedException(typeof(NotSupportedQueryFragmentException))]
         public void CollationConflict()
         {
-            var planBuilder = new ExecutionPlanBuilder(_dataSources.Values, new OptionsWrapper(this) { PrimaryDataSource = "prod" });
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_dataSources, new OptionsWrapper(this) { PrimaryDataSource = "prod" }), new OptionsWrapper(this) { PrimaryDataSource = "prod" });
             var query = "SELECT * FROM prod.dbo.account p, french.dbo.account f WHERE p.name = f.name";
             planBuilder.Build(query, null, out _);
         }
@@ -5934,7 +5940,7 @@ public void CollationConflict()
         [TestMethod]
         public void CollationConflictJoin()
         {
-            var planBuilder = new ExecutionPlanBuilder(_dataSources.Values, new OptionsWrapper(this) { PrimaryDataSource = "prod" });
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_dataSources, new OptionsWrapper(this) { PrimaryDataSource = "prod" }), new OptionsWrapper(this) { PrimaryDataSource = "prod" });
             var query = "SELECT * FROM prod.dbo.account p INNER JOIN french.dbo.account f ON p.name = f.name";
 
             try
@@ -5951,7 +5957,7 @@ public void CollationConflictJoin()
         [TestMethod]
         public void TypeConflictJoin()
         {
-            var planBuilder = new ExecutionPlanBuilder(_dataSources.Values, new OptionsWrapper(this) { PrimaryDataSource = "prod" });
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_dataSources, new OptionsWrapper(this) { PrimaryDataSource = "prod" }), new OptionsWrapper(this) { PrimaryDataSource = "prod" });
             var query = "SELECT * FROM account p INNER JOIN account f ON p.accountid = f.turnover";
 
             try
@@ -5968,7 +5974,7 @@ public void TypeConflictJoin()
         [TestMethod]
         public void TypeConflictCrossInstanceJoin()
         {
-            var planBuilder = new ExecutionPlanBuilder(_dataSources.Values, new OptionsWrapper(this) { PrimaryDataSource = "prod" });
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_dataSources, new OptionsWrapper(this) { PrimaryDataSource = "prod" }), new OptionsWrapper(this) { PrimaryDataSource = "prod" });
             var query = "SELECT * FROM prod.dbo.account p INNER JOIN french.dbo.account f ON p.accountid = f.turnover";
 
             try
@@ -5985,7 +5991,7 @@ public void TypeConflictCrossInstanceJoin()
         [TestMethod]
         public void ExplicitCollation()
         {
-            var planBuilder = new ExecutionPlanBuilder(_dataSources.Values, new OptionsWrapper(this) { PrimaryDataSource = "prod" });
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_dataSources, new OptionsWrapper(this) { PrimaryDataSource = "prod" }), new OptionsWrapper(this) { PrimaryDataSource = "prod" });
             var query = "SELECT * FROM prod.dbo.account p, french.dbo.account f WHERE p.name = f.name COLLATE French_CI_AS";
             var plans = planBuilder.Build(query, null, out _);
 
@@ -6022,7 +6028,7 @@ public void ExplicitCollation()
         [ExpectedException(typeof(NotSupportedQueryFragmentException))]
         public void NoCollationSelectListError()
         {
-            var planBuilder = new ExecutionPlanBuilder(_dataSources.Values, new OptionsWrapper(this) { PrimaryDataSource = "prod" });
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_dataSources, new OptionsWrapper(this) { PrimaryDataSource = "prod" }), new OptionsWrapper(this) { PrimaryDataSource = "prod" });
             var query = "SELECT (CASE WHEN p.employees > f.employees THEN p.name ELSE f.name END) FROM prod.dbo.account p, french.dbo.account f";
             planBuilder.Build(query, null, out _);
         }
@@ -6030,7 +6036,7 @@ public void NoCollationSelectListError()
         [TestMethod]
         public void NoCollationExprWithExplicitCollationSelectList()
         {
-            var planBuilder = new ExecutionPlanBuilder(_dataSources.Values, new OptionsWrapper(this) { PrimaryDataSource = "prod" });
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_dataSources, new OptionsWrapper(this) { PrimaryDataSource = "prod" }), new OptionsWrapper(this) { PrimaryDataSource = "prod" });
             var query = "SELECT (CASE WHEN p.employees > f.employees THEN p.name ELSE f.name END) COLLATE Latin1_General_CI_AS FROM prod.dbo.account p, french.dbo.account f";
             planBuilder.Build(query, null, out _);
         }
@@ -6039,7 +6045,7 @@ public void NoCollationExprWithExplicitCollationSelectList()
         [ExpectedException(typeof(NotSupportedQueryFragmentException))]
         public void NoCollationCollationSensitiveFunctionError()
         {
-            var planBuilder = new ExecutionPlanBuilder(_dataSources.Values, new OptionsWrapper(this) { PrimaryDataSource = "prod" });
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_dataSources, new OptionsWrapper(this) { PrimaryDataSource = "prod" }), new OptionsWrapper(this) { PrimaryDataSource = "prod" });
             var query = "SELECT PATINDEX((CASE WHEN p.employees > f.employees THEN p.name ELSE f.name END), 'a') FROM prod.dbo.account p, french.dbo.account f";
             planBuilder.Build(query, null, out _);
         }
@@ -6047,7 +6053,7 @@ public void NoCollationCollationSensitiveFunctionError()
         [TestMethod]
         public void NoCollationExprWithExplicitCollationCollationSensitiveFunctionError()
         {
-            var planBuilder = new ExecutionPlanBuilder(_dataSources.Values, new OptionsWrapper(this) { PrimaryDataSource = "prod" });
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_dataSources, new OptionsWrapper(this) { PrimaryDataSource = "prod" }), new OptionsWrapper(this) { PrimaryDataSource = "prod" });
             var query = "SELECT PATINDEX((CASE WHEN p.employees > f.employees THEN p.name ELSE f.name END) COLLATE Latin1_General_CI_AS, 'a') FROM prod.dbo.account p, french.dbo.account f";
             planBuilder.Build(query, null, out _);
         }
@@ -6055,7 +6061,7 @@ public void NoCollationExprWithExplicitCollationCollationSensitiveFunctionError(
         [TestMethod]
         public void CollationFunctions()
         {
-            var planBuilder = new ExecutionPlanBuilder(_dataSources.Values, new OptionsWrapper(this) { PrimaryDataSource = "prod" });
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_dataSources, new OptionsWrapper(this) { PrimaryDataSource = "prod" }), new OptionsWrapper(this) { PrimaryDataSource = "prod" });
             var query = "SELECT *, COLLATIONPROPERTY(name, 'lcid') FROM sys.fn_helpcollations()";
             var plans = planBuilder.Build(query, null, out _);
 
@@ -6071,7 +6077,7 @@ public void CollationFunctions()
         [ExpectedException(typeof(NotSupportedQueryFragmentException))]
         public void DuplicatedTableName()
         {
-            var planBuilder = new ExecutionPlanBuilder(_dataSources.Values, new OptionsWrapper(this) { PrimaryDataSource = "prod" });
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_dataSources, new OptionsWrapper(this) { PrimaryDataSource = "prod" }), new OptionsWrapper(this) { PrimaryDataSource = "prod" });
             var query = "SELECT * FROM account, account";
             planBuilder.Build(query, null, out _);
         }
@@ -6080,7 +6086,7 @@ public void DuplicatedTableName()
         [ExpectedException(typeof(NotSupportedQueryFragmentException))]
         public void DuplicatedTableNameJoin()
         {
-            var planBuilder = new ExecutionPlanBuilder(_dataSources.Values, new OptionsWrapper(this) { PrimaryDataSource = "prod" });
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_dataSources, new OptionsWrapper(this) { PrimaryDataSource = "prod" }), new OptionsWrapper(this) { PrimaryDataSource = "prod" });
             var query = "SELECT * FROM account INNER JOIN contact ON contact.parentcustomerid = account.accountid INNER JOIN contact ON contact.parentcustomerid = account.accountid";
             planBuilder.Build(query, null, out _);
         }
@@ -6089,7 +6095,7 @@ public void DuplicatedTableNameJoin()
         [ExpectedException(typeof(NotSupportedQueryFragmentException))]
         public void DuplicatedAliasName()
         {
-            var planBuilder = new ExecutionPlanBuilder(_dataSources.Values, new OptionsWrapper(this) { PrimaryDataSource = "prod" });
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_dataSources, new OptionsWrapper(this) { PrimaryDataSource = "prod" }), new OptionsWrapper(this) { PrimaryDataSource = "prod" });
             var query = "SELECT * FROM account x INNER JOIN contact x ON x.parentcustomerid = x.accountid";
             planBuilder.Build(query, null, out _);
         }
@@ -6098,7 +6104,7 @@ public void DuplicatedAliasName()
         [ExpectedException(typeof(NotSupportedQueryFragmentException))]
         public void TableNameMatchesAliasName()
         {
-            var planBuilder = new ExecutionPlanBuilder(_dataSources.Values, new OptionsWrapper(this) { PrimaryDataSource = "prod" });
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_dataSources, new OptionsWrapper(this) { PrimaryDataSource = "prod" }), new OptionsWrapper(this) { PrimaryDataSource = "prod" });
             var query = "SELECT * FROM account INNER JOIN contact AS account ON account.parentcustomerid = account.accountid";
             planBuilder.Build(query, null, out _);
         }
@@ -6108,7 +6114,7 @@ public void AuditJoinsToCallingUserIdAndUserId()
         {
             // https://learn.microsoft.com/en-us/power-apps/developer/data-platform/auditing/retrieve-audit-data?tabs=webapi#audit-table-relationships
             // Audit table can only be joined to systemuser on callinguserid or userid. Both joins together, or any other joins, are not valid.
-            var planBuilder = new ExecutionPlanBuilder(_dataSources.Values, new OptionsWrapper(this) { PrimaryDataSource = "prod" });
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_dataSources, new OptionsWrapper(this) { PrimaryDataSource = "prod" }), new OptionsWrapper(this) { PrimaryDataSource = "prod" });
             var query = "SELECT * FROM audit INNER JOIN systemuser cu ON audit.callinguserid = cu.systemuserid INNER JOIN systemuser u ON audit.userid = u.systemuserid";
             var plans = planBuilder.Build(query, null, out _);
 
@@ -6146,7 +6152,7 @@ public void AuditJoinsToObjectId()
         {
             // https://learn.microsoft.com/en-us/power-apps/developer/data-platform/auditing/retrieve-audit-data?tabs=webapi#audit-table-relationships
             // Audit table can only be joined to systemuser on callinguserid or userid. Both joins together, or any other joins, are not valid.
-            var planBuilder = new ExecutionPlanBuilder(_dataSources.Values, new OptionsWrapper(this) { PrimaryDataSource = "prod" });
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_dataSources, new OptionsWrapper(this) { PrimaryDataSource = "prod" }), new OptionsWrapper(this) { PrimaryDataSource = "prod" });
             var query = "SELECT * FROM audit INNER JOIN account ON audit.objectid = account.accountid";
             var plans = planBuilder.Build(query, null, out _);
 
@@ -6180,7 +6186,7 @@ public void AuditJoinsToObjectId()
         public void SelectAuditObjectId()
         {
             // https://github.com/MarkMpn/Sql4Cds/issues/296
-            var planBuilder = new ExecutionPlanBuilder(_dataSources.Values, new OptionsWrapper(this) { PrimaryDataSource = "prod" });
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_dataSources, new OptionsWrapper(this) { PrimaryDataSource = "prod" }), new OptionsWrapper(this) { PrimaryDataSource = "prod" });
             var query = "SELECT auditid, objectidtype AS o FROM audit";
             var plans = planBuilder.Build(query, null, out _);
 
@@ -6207,7 +6213,7 @@ public void SelectAuditObjectIdDistinct(string column)
             // https://github.com/MarkMpn/Sql4Cds/issues/519
             // We need to add the objecttypecode attribute to the FetchXML for the first issue, but combining this
             // with DISTINCT doesn't work because of the second issue.
-            var planBuilder = new ExecutionPlanBuilder(_dataSources.Values, new OptionsWrapper(this) { PrimaryDataSource = "prod" });
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_dataSources, new OptionsWrapper(this) { PrimaryDataSource = "prod" }), new OptionsWrapper(this) { PrimaryDataSource = "prod" });
             var query = $"SELECT DISTINCT {column} AS o FROM audit";
             var plans = planBuilder.Build(query, null, out _);
 
@@ -6227,7 +6233,7 @@ public void SelectAuditObjectIdDistinct(string column)
         [TestMethod]
         public void FilterAuditOnLeftJoinColumn()
         {
-            var planBuilder = new ExecutionPlanBuilder(_dataSources.Values, new OptionsWrapper(this) { PrimaryDataSource = "prod" });
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_dataSources, new OptionsWrapper(this) { PrimaryDataSource = "prod" }), new OptionsWrapper(this) { PrimaryDataSource = "prod" });
             var query = "SELECT * FROM audit LEFT OUTER JOIN systemuser ON audit.userid = systemuser.systemuserid WHERE systemuser.domainname IS NULL";
             var plans = planBuilder.Build(query, null, out _);
 
@@ -6249,7 +6255,7 @@ public void FilterAuditOnLeftJoinColumn()
         [TestMethod]
         public void FilterAuditOnUserId()
         {
-            var planBuilder = new ExecutionPlanBuilder(_dataSources.Values, new OptionsWrapper(this) { PrimaryDataSource = "prod" });
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_dataSources, new OptionsWrapper(this) { PrimaryDataSource = "prod" }), new OptionsWrapper(this) { PrimaryDataSource = "prod" });
             var query = "SELECT * FROM audit WHERE userid = 'B52C0694-E16F-40CD-9F27-800023C47A98'";
             var plans = planBuilder.Build(query, null, out _);
 
@@ -6272,7 +6278,7 @@ public void FilterAuditOnUserIdAggregate()
         {
             // Can do aggregates on audit table when any filtering is done only on the table itself,
             // not on any joins
-            var planBuilder = new ExecutionPlanBuilder(_dataSources.Values, new OptionsWrapper(this) { PrimaryDataSource = "prod" });
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_dataSources, new OptionsWrapper(this) { PrimaryDataSource = "prod" }), new OptionsWrapper(this) { PrimaryDataSource = "prod" });
             var query = "SELECT COUNT(*) FROM audit WHERE userid = 'B52C0694-E16F-40CD-9F27-800023C47A98'";
             var plans = planBuilder.Build(query, null, out _);
 
@@ -6305,7 +6311,7 @@ public void FilterAuditOnUserIdAggregate()
         [TestMethod]
         public void FilterAuditOnInnerJoinColumn()
         {
-            var planBuilder = new ExecutionPlanBuilder(_dataSources.Values, new OptionsWrapper(this) { PrimaryDataSource = "prod" });
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_dataSources, new OptionsWrapper(this) { PrimaryDataSource = "prod" }), new OptionsWrapper(this) { PrimaryDataSource = "prod" });
             var query = "SELECT * FROM audit INNER JOIN systemuser ON audit.userid = systemuser.systemuserid WHERE systemuser.domainname <> 'SYSTEM'";
             var plans = planBuilder.Build(query, null, out _);
 
@@ -6332,7 +6338,7 @@ public void FilterAuditOnInnerJoinColumnAggregate()
         {
             // Can't do aggregates on audit table when filtering is done on a join
             // https://github.com/MarkMpn/Sql4Cds/issues/488
-            var planBuilder = new ExecutionPlanBuilder(_dataSources.Values, new OptionsWrapper(this) { PrimaryDataSource = "prod" });
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_dataSources, new OptionsWrapper(this) { PrimaryDataSource = "prod" }), new OptionsWrapper(this) { PrimaryDataSource = "prod" });
             var query = "SELECT COUNT(*) FROM audit INNER JOIN systemuser ON audit.userid = systemuser.systemuserid WHERE systemuser.domainname <> 'SYSTEM'";
             var plans = planBuilder.Build(query, null, out _);
 
@@ -6357,7 +6363,7 @@ public void FilterAuditOnInnerJoinColumnAggregate()
         [TestMethod]
         public void SortAuditOnJoinColumn()
         {
-            var planBuilder = new ExecutionPlanBuilder(_dataSources.Values, new OptionsWrapper(this) { PrimaryDataSource = "prod" });
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_dataSources, new OptionsWrapper(this) { PrimaryDataSource = "prod" }), new OptionsWrapper(this) { PrimaryDataSource = "prod" });
             var query = "SELECT * FROM audit LEFT OUTER JOIN systemuser ON audit.userid = systemuser.systemuserid ORDER BY systemuser.domainname";
             var plans = planBuilder.Build(query, null, out _);
 
@@ -6379,7 +6385,7 @@ public void SortAuditOnJoinColumn()
         [TestMethod]
         public void NestedSubqueries()
         {
-            var planBuilder = new ExecutionPlanBuilder(_dataSources.Values, new OptionsWrapper(this) { PrimaryDataSource = "prod" });
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_dataSources, new OptionsWrapper(this) { PrimaryDataSource = "prod" }), new OptionsWrapper(this) { PrimaryDataSource = "prod" });
             var query = @"
                 SELECT name,
                     (select STUFF((SELECT ', ' + fullname
@@ -6403,7 +6409,7 @@ FOR    XML PATH ('')), 1, 2, ''))
         [TestMethod]
         public void CalculatedColumnUsesEmptyName()
         {
-            var planBuilder = new ExecutionPlanBuilder(_dataSources.Values, new OptionsWrapper(this) { PrimaryDataSource = "prod" });
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_dataSources, new OptionsWrapper(this) { PrimaryDataSource = "prod" }), new OptionsWrapper(this) { PrimaryDataSource = "prod" });
             var query = @"SELECT (select STUFF('abcdef', 2, 3, 'ijklmn'))";
             var plans = planBuilder.Build(query, null, out _);
 
@@ -6415,7 +6421,7 @@ public void CalculatedColumnUsesEmptyName()
         [TestMethod]
         public void OuterJoinWithFiltersConvertedToInnerJoin()
         {
-            var planBuilder = new ExecutionPlanBuilder(_dataSources.Values, new OptionsWrapper(this) { PrimaryDataSource = "prod" });
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_dataSources, new OptionsWrapper(this) { PrimaryDataSource = "prod" }), new OptionsWrapper(this) { PrimaryDataSource = "prod" });
             var outerJoinQuery = "SELECT * FROM account LEFT OUTER JOIN contact ON contact.parentcustomerid = account.accountid WHERE contact.firstname = 'Mark'";
             var outerJoinPlans = planBuilder.Build(outerJoinQuery, null, out _);
 
@@ -6437,7 +6443,7 @@ public void OuterJoinWithFiltersConvertedToInnerJoin()
         public void CorrelatedSubqueryWithMultipleConditions()
         {
             // https://github.com/MarkMpn/Sql4Cds/issues/316
-            var planBuilder = new ExecutionPlanBuilder(_dataSources.Values, new OptionsWrapper(this) { PrimaryDataSource = "prod" });
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_dataSources, new OptionsWrapper(this) { PrimaryDataSource = "prod" }), new OptionsWrapper(this) { PrimaryDataSource = "prod" });
             var query = @"
 SELECT r.accountid,
        r.employees,
@@ -6530,10 +6536,14 @@ public void CrossInstanceJoinOnStringColumn()
                 new DataSource
                 {
                     Name = "local", // Hack so that ((IQueryExecutionOptions)this).PrimaryDataSource = "local" doesn't cause test to fail
+                    Connection = _context2.GetOrganizationService(),
+                    Metadata = metadata2,
+                    TableSizeCache = new StubTableSizeCache(),
+                    MessageCache = new StubMessageCache(),
                     DefaultCollation = Collation.USEnglish
                 }
             };
-            var planBuilder = new ExecutionPlanBuilder(datasources, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(datasources.ToDictionary(d => d.Name), this), this);
 
             var query = "SELECT uat.name, prod.name FROM uat.dbo.account AS uat INNER JOIN prod.dbo.account AS prod ON uat.name = prod.name";
 
@@ -6575,7 +6585,7 @@ public void CrossInstanceJoinOnStringColumn()
         [TestMethod]
         public void LiftOrFilterToLinkEntityWithInnerJoin()
         {
-            var planBuilder = new ExecutionPlanBuilder(_dataSources.Values, new OptionsWrapper(this) { PrimaryDataSource = "prod" });
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_dataSources, new OptionsWrapper(this) { PrimaryDataSource = "prod" }), new OptionsWrapper(this) { PrimaryDataSource = "prod" });
             var query = "SELECT * FROM contact INNER JOIN account ON contact.parentcustomerid = account.accountid WHERE account.name = 'Data8' OR account.name = 'Data 8'";
             var plans = planBuilder.Build(query, null, out _);
 
@@ -6600,7 +6610,7 @@ public void LiftOrFilterToLinkEntityWithInnerJoin()
         [TestMethod]
         public void DoNotLiftOrFilterToLinkEntityWithOuterJoin()
         {
-            var planBuilder = new ExecutionPlanBuilder(_dataSources.Values, new OptionsWrapper(this) { PrimaryDataSource = "prod" });
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_dataSources, new OptionsWrapper(this) { PrimaryDataSource = "prod" }), new OptionsWrapper(this) { PrimaryDataSource = "prod" });
             var query = "SELECT * FROM contact LEFT OUTER JOIN account ON contact.parentcustomerid = account.accountid WHERE account.name = 'Data8' OR account.name = 'Data 8'";
             var plans = planBuilder.Build(query, null, out _);
 
@@ -6625,7 +6635,7 @@ public void DoNotLiftOrFilterToLinkEntityWithOuterJoin()
         [TestMethod]
         public void DoNotLiftOrFilterToLinkEntityWithDifferentEntities()
         {
-            var planBuilder = new ExecutionPlanBuilder(_dataSources.Values, new OptionsWrapper(this) { PrimaryDataSource = "prod" });
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_dataSources, new OptionsWrapper(this) { PrimaryDataSource = "prod" }), new OptionsWrapper(this) { PrimaryDataSource = "prod" });
             var query = "SELECT * FROM contact LEFT OUTER JOIN account ON contact.parentcustomerid = account.accountid WHERE account.name = 'Data8' OR contact.fullname = 'Mark Carrington'";
             var plans = planBuilder.Build(query, null, out _);
 
@@ -6650,7 +6660,7 @@ public void DoNotLiftOrFilterToLinkEntityWithDifferentEntities()
         [TestMethod]
         public void FoldSortOrderToInnerJoinLeftInput()
         {
-            var planBuilder = new ExecutionPlanBuilder(_dataSources.Values, new OptionsWrapper(this) { PrimaryDataSource = "prod" });
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_dataSources, new OptionsWrapper(this) { PrimaryDataSource = "prod" }), new OptionsWrapper(this) { PrimaryDataSource = "prod" });
             var query = "SELECT TOP 10 audit.* FROM contact CROSS APPLY SampleMessage(firstname) AS audit WHERE firstname = 'Mark' ORDER BY contact.createdon;";
             var plans = planBuilder.Build(query, null, out _);
 
@@ -6675,7 +6685,7 @@ public void FoldSortOrderToInnerJoinLeftInput()
         [TestMethod]
         public void UpdateFromSubquery()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = "UPDATE account SET name = 'foo' FROM account INNER JOIN (SELECT name, MIN(createdon) FROM account GROUP BY name HAVING COUNT(*) > 1) AS dupes ON account.name = dupes.name";
 
@@ -6699,7 +6709,7 @@ public void UpdateFromSubquery()
         [TestMethod]
         public void MinPrimaryKey()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = "SELECT MIN(accountid) FROM account";
 
@@ -6721,7 +6731,7 @@ public void MinPrimaryKey()
         [TestMethod]
         public void MinPicklist()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = "SELECT MIN(new_optionsetvalue) FROM new_customentity";
 
@@ -6744,7 +6754,7 @@ public void MinPicklist()
         [ExpectedException(typeof(NotSupportedQueryFragmentException))]
         public void AvgGuidIsNotSupported()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
             var query = "SELECT AVG(accountid) FROM account";
             planBuilder.Build(query, null, out _);
         }
@@ -6752,7 +6762,7 @@ public void AvgGuidIsNotSupported()
         [TestMethod]
         public void StringAggWithOrderAndNoGroups()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = "SELECT STRING_AGG(name, ',') WITHIN GROUP (ORDER BY name DESC) FROM account";
 
@@ -6775,7 +6785,7 @@ public void StringAggWithOrderAndNoGroups()
         [TestMethod]
         public void StringAggWithOrderAndScalarGroups()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = "SELECT STRING_AGG(name, ',') WITHIN GROUP (ORDER BY name DESC) FROM account GROUP BY employees";
 
@@ -6800,7 +6810,7 @@ public void StringAggWithOrderAndScalarGroups()
         [TestMethod]
         public void StringAggWithOrderAndNonScalarGroups()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = "SELECT STRING_AGG(name, ',') WITHIN GROUP (ORDER BY name DESC) FROM account GROUP BY name + 'x'";
 
@@ -6824,7 +6834,7 @@ public void StringAggWithOrderAndNonScalarGroups()
         [TestMethod]
         public void NestedExistsAndIn()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = "IF NOT EXISTS(SELECT * FROM account WHERE primarycontactid IN (SELECT contactid FROM contact WHERE firstname = 'Mark')) SELECT 1";
 
@@ -6835,7 +6845,7 @@ public void NestedExistsAndIn()
         [TestMethod]
         public void HashJoinUsedForDifferentDataTypes()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = "SELECT * FROM account WHERE EXISTS(SELECT * FROM contact WHERE account.name = contact.createdon)";
 
@@ -6866,7 +6876,7 @@ public void DoNotFoldFilterOnParameterToIndexSpool()
         {
             // Subquery on right side of nested loop will use an index spool to reduce number of FetchXML requests. Do not use this logic if the
             // filter variable is an external parameter or the FetchXML is on the left side of the loop
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = "SELECT * FROM account WHERE name = @name and primarycontactid = (SELECT contactid FROM contact WHERE firstname = 'Mark')";
 
@@ -6917,7 +6927,7 @@ public void DoNotFoldFilterOnParameterToIndexSpool()
         [TestMethod]
         public void DoNotFoldJoinsOnReusedAliases()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 SELECT s.systemuserid,
@@ -6988,7 +6998,7 @@ systemuser AS s
         [TestMethod]
         public void ComplexFetchXmlAlias()
         {
-            var planBuilder = new ExecutionPlanBuilder(_dataSources.Values, new OptionsWrapper(this) { PrimaryDataSource = "uat" });
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_dataSources, new OptionsWrapper(this) { PrimaryDataSource = "uat" }), new OptionsWrapper(this) { PrimaryDataSource = "uat" });
 
             var query = "SELECT name FROM account AS [acc. table]";
 
@@ -7004,7 +7014,7 @@ public void ComplexFetchXmlAlias()
         [TestMethod]
         public void ComplexMetadataAlias()
         {
-            var planBuilder = new ExecutionPlanBuilder(_dataSources.Values, new OptionsWrapper(this) { PrimaryDataSource = "uat" });
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_dataSources, new OptionsWrapper(this) { PrimaryDataSource = "uat" }), new OptionsWrapper(this) { PrimaryDataSource = "uat" });
 
             var query = "SELECT logicalname FROM metadata.entity AS [m.d. table] WHERE [m.d. table].logicalname = 'account'";
 
@@ -7023,7 +7033,7 @@ public void ComplexMetadataAlias()
         [TestMethod]
         public void ComplexInlineTableAlias()
         {
-            var planBuilder = new ExecutionPlanBuilder(_dataSources.Values, new OptionsWrapper(this) { PrimaryDataSource = "uat" });
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_dataSources, new OptionsWrapper(this) { PrimaryDataSource = "uat" }), new OptionsWrapper(this) { PrimaryDataSource = "uat" });
 
             var query = "SELECT [full name] FROM (VALUES ('Mark Carrington')) AS [inline table] ([full name])";
 
@@ -7041,7 +7051,7 @@ public void ComplexInlineTableAlias()
         [TestMethod]
         public void FoldFiltersToUnionAllAndJoins()
         {
-            var planBuilder = new ExecutionPlanBuilder(_dataSources.Values, new OptionsWrapper(this) { PrimaryDataSource = "uat" });
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_dataSources, new OptionsWrapper(this) { PrimaryDataSource = "uat" }), new OptionsWrapper(this) { PrimaryDataSource = "uat" });
 
             var query = @"
 SELECT   [union. all].eln,
@@ -7117,7 +7127,7 @@ AND [union. all].logicalname IN ('createdon')
         [TestMethod]
         public void PreserveAdditionalFiltersInMetadataJoinConditions()
         {
-            var planBuilder = new ExecutionPlanBuilder(_dataSources.Values, new OptionsWrapper(this) { PrimaryDataSource = "uat" });
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_dataSources, new OptionsWrapper(this) { PrimaryDataSource = "uat" }), new OptionsWrapper(this) { PrimaryDataSource = "uat" });
 
             var query = @"
 SELECT e.logicalname,
@@ -7153,7 +7163,7 @@ public void FoldFilterToJoinWithAlias()
             // Filter is applied to a join with a LHS of FetchXmlScan, which the filter can be entirely folded to
             // Exception is thrown when trying to fold the remaining null filter to the RHS of the join
 
-            var planBuilder = new ExecutionPlanBuilder(_dataSources.Values, new OptionsWrapper(this) { PrimaryDataSource = "uat" });
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_dataSources, new OptionsWrapper(this) { PrimaryDataSource = "uat" }), new OptionsWrapper(this) { PrimaryDataSource = "uat" });
 
             var query = @"
 SELECT app.*
@@ -7176,7 +7186,7 @@ public void DoNotUseCustomPagingForInJoin()
 
             using (_dataSource.EnableJoinOperator(JoinOperator.In))
             {
-                var planBuilder = new ExecutionPlanBuilder(_dataSources.Values, new OptionsWrapper(this) { PrimaryDataSource = "uat" });
+                var planBuilder = new ExecutionPlanBuilder(new SessionContext(_dataSources, new OptionsWrapper(this) { PrimaryDataSource = "uat" }), new OptionsWrapper(this) { PrimaryDataSource = "uat" });
 
                 var query = @"
 SELECT contactid
@@ -7215,7 +7225,7 @@ public void FoldFilterToCorrectTableAlias()
             // The same table alias can be used in the main query and in a query-derived table. Ensure filters are
             // folded to the correct one.
 
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
 SELECT *
@@ -7259,7 +7269,7 @@ public void FoldFilterToCorrectTableAlias()
         [TestMethod]
         public void IgnoreDupKeyHint()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"INSERT INTO account (accountid, name) VALUES ('{CD503427-E785-40D8-AD0E-FBDF4918D298}', 'Data8') OPTION (USE HINT ('IGNORE_DUP_KEY'))";
 
@@ -7274,7 +7284,7 @@ public void IgnoreDupKeyHint()
         [TestMethod]
         public void GroupByWithoutAggregateUsesDistinct()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
                 SELECT
@@ -7301,7 +7311,7 @@ public void GroupByWithoutAggregateUsesDistinct()
         [TestMethod]
         public void FilterOnCrossApply()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
 select name, n from account
@@ -7337,7 +7347,7 @@ cross apply (select name + '' as n) x
         [TestMethod]
         public void GotoCantMoveIntoTryBlock()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
 GOTO label1
@@ -7364,7 +7374,7 @@ BEGIN CATCH
         [DataRow(3)]
         public void UpdateTop(int top)
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = $@"
 UPDATE account
@@ -7399,7 +7409,7 @@ AND employees > 0
         [TestMethod]
         public void RethrowMustBeWithinCatchBlock()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = "THROW;";
 
@@ -7417,7 +7427,7 @@ public void RethrowMustBeWithinCatchBlock()
         [TestMethod]
         public void MistypedJoinCriteriaGeneratesWarning()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
 SELECT a.name, c.fullname
@@ -7457,7 +7467,7 @@ public void MistypedJoinCriteriaGeneratesWarning()
         [TestMethod]
         public void AliasSameAsVirtualAttribute()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
 select a.name, c.fullname as primarycontactidname from account a
@@ -7483,7 +7493,7 @@ public void AliasSameAsVirtualAttribute()
         [TestMethod]
         public void OrderByOptionSetName()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"SELECT new_customentityid FROM new_customentity ORDER BY new_optionsetvaluename";
 
@@ -7507,7 +7517,7 @@ public void OrderByOptionSetValueWithUseRawOrderBy()
         {
             using (_localDataSource.SetUseRawOrderByReliable(true))
             {
-                var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+                var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
                 var query = @"SELECT new_customentityid FROM new_customentity ORDER BY new_optionsetvalue";
 
@@ -7530,7 +7540,7 @@ public void OrderByOptionSetValueWithUseRawOrderBy()
         [TestMethod]
         public void OrderByOptionSetValueWithoutUseRawOrderBy()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"SELECT new_customentityid FROM new_customentity ORDER BY new_optionsetvalue";
 
@@ -7556,7 +7566,7 @@ public void OrderByOptionSetValueAndName()
         {
             using (_localDataSource.SetUseRawOrderByReliable(true))
             {
-                var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+                var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
                 var query = @"SELECT new_customentityid FROM new_customentity ORDER BY new_optionsetvalue, new_optionsetvaluename";
 
@@ -7587,7 +7597,7 @@ public void ExistsOrInAndColumnComparisonOrderByEntityName()
             using (_localDataSource.EnableJoinOperator(JoinOperator.Any))
             using (_localDataSource.SetOrderByEntityName(true))
             {
-                var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+                var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
                 var query = @"
 SELECT TOP 100
@@ -7646,7 +7656,7 @@ public void ExistsOrInAndColumnComparisonOrderByEntityNameLegacy()
         {
             using (_localDataSource.SetColumnComparison(false))
             {
-                var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+                var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
                 var query = @"
 SELECT TOP 100
@@ -7723,7 +7733,7 @@ ORDER BY
         [TestMethod]
         public void DistinctUsesCustomPaging()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
 select distinct
@@ -7755,7 +7765,7 @@ from account
         [TestMethod]
         public void NotExistWithJoin()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
 select top 10 a2.name
@@ -7824,7 +7834,7 @@ from account a
         [TestMethod]
         public void ScalarSubquery()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
 select top 10 * from (
@@ -7854,7 +7864,7 @@ public void SubqueryInJoinCriteriaRHS()
         {
             using (_localDataSource.EnableJoinOperator(JoinOperator.In))
             {
-                var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+                var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
                 var query = @"
 select
@@ -7887,7 +7897,7 @@ public void SubqueryInJoinCriteriaRHSCorrelatedExists()
         {
             using (_localDataSource.EnableJoinOperator(JoinOperator.In))
             {
-                var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+                var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
                 var query = @"
 select
@@ -7920,7 +7930,7 @@ public void SubqueryInJoinCriteriaLHS()
         {
             using (_localDataSource.EnableJoinOperator(JoinOperator.In))
             {
-                var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+                var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
                 var query = @"
 select
@@ -7953,7 +7963,7 @@ public void SubqueryInJoinCriteriaLHSCorrelatedExists()
         {
             using (_localDataSource.EnableJoinOperator(JoinOperator.In))
             {
-                var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+                var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
                 var query = @"
 select
@@ -7986,7 +7996,7 @@ public void SubqueryInJoinCriteriaLHSAndRHSInnerJoin()
         {
             using (_localDataSource.EnableJoinOperator(JoinOperator.In))
             {
-                var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+                var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
                 var query = @"
 select
@@ -8040,7 +8050,7 @@ public void SubqueryInJoinCriteriaLHSAndRHSOuterJoin()
         {
             using (_localDataSource.EnableJoinOperator(JoinOperator.In))
             {
-                var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+                var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
                 var query = @"
 select
@@ -8102,7 +8112,7 @@ from account
         [TestMethod]
         public void VirtualAttributeAliases()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
 select statecodename [state], parentcustomerid x, parentcustomeridname from contact";
@@ -8138,7 +8148,7 @@ FROM account as a
 LEFT JOIN account AS ca ON c.contactid = ca.primarycontactid
 WHERE c.parentcustomerid IN (SELECT contactid FROM contact WHERE createdon = today())";
 
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var plans = planBuilder.Build(query, null, out _);
 
@@ -8188,7 +8198,7 @@ FROM account as a
 LEFT JOIN account AS ca ON c.contactid = ca.primarycontactid
 WHERE c.contactid IN (SELECT contactid FROM contact WHERE createdon = today())";
 
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var plans = planBuilder.Build(query, null, out _);
 
@@ -8236,7 +8246,7 @@ metadata.entity AS p
        ON a.targets = p.logicalname
 WHERE  a.entitylogicalname IN ('team')";
 
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var plans = planBuilder.Build(query, null, out _);
 
@@ -8260,7 +8270,7 @@ FROM account
 WHERE createdon >= CAST(GETDATE() AS DATE)
 AND createdon < DATEADD(day, 1, CAST(GETDATE() AS DATE))";
 
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var plans = planBuilder.Build(query, null, out _);
 
@@ -8293,7 +8303,7 @@ FROM new_customentity
 WHERE new_name IN ('test')) AS a
 ORDER BY a.new_customentityid";
 
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var plans = planBuilder.Build(query, null, out _);
 
@@ -8330,7 +8340,7 @@ FROM new_customentity
 WHERE new_name IN ('test')) AS a
 ORDER BY a.new_customentityid";
 
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var plans = planBuilder.Build(query, null, out _);
 
@@ -8364,7 +8374,7 @@ LEFT OUTER JOIN
        (SELECT a.parentaccountid, a.name AS test FROM account a) AS a2
        ON a2.parentaccountid = a1.accountid";
 
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var plans = planBuilder.Build(query, null, out _);
 
@@ -8408,7 +8418,7 @@ LEFT OUTER JOIN
         public void EntityKeyIndexStatusFilter()
         {
             // https://github.com/MarkMpn/Sql4Cds/issues/534
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
 SELECT ak.entitylogicalname,
@@ -8438,7 +8448,7 @@ FROM   metadata.alternate_key AS ak
         public void OuterApplyOuterReference()
         {
             // https://github.com/MarkMpn/Sql4Cds/issues/547
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
 SELECT *
@@ -8478,7 +8488,7 @@ OUTER APPLY (
         public void FilterOnOuterApply()
         {
             // https://github.com/MarkMpn/Sql4Cds/issues/548
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
 SELECT *
@@ -8511,7 +8521,7 @@ SELECT IIF(q1.name = 'Test1', 1, 0) AS [flag1],
         [TestMethod]
         public void ScalarSubqueryWithoutAlias()
         {
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
 
             var query = @"
 SELECT a.accountid,
@@ -8532,6 +8542,132 @@ public void ScalarSubqueryWithoutAlias()
             <attribute name='fullname' />
         </link-entity>
     </entity>
+</fetch>");
+        }
+
+        [TestMethod]
+        public void DeleteByIdUsesConstantScan()
+        {
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
+
+            var query = "DELETE FROM account WHERE accountid = '1D3AACA6-DEA4-490F-973E-E4181D4BE11C'";
+
+            var plans = planBuilder.Build(query, null, out _);
+
+            Assert.AreEqual(1, plans.Length);
+
+            var delete = AssertNode<DeleteNode>(plans[0]);
+            var constant = AssertNode<ConstantScanNode>(delete.Source);
+        }
+
+        [TestMethod]
+        public void DeleteByIdWithGlobalVariableUsesConstantScan()
+        {
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
+
+            var query = "DELETE FROM account WHERE accountid = @@IDENTITY";
+
+            var plans = planBuilder.Build(query, null, out _);
+
+            Assert.AreEqual(1, plans.Length);
+
+            var delete = AssertNode<DeleteNode>(plans[0]);
+            var constant = AssertNode<ConstantScanNode>(delete.Source);
+        }
+
+        [TestMethod]
+        public void DeleteByIdWithVariableUsesConstantScan()
+        {
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
+
+            var query = "DELETE FROM account WHERE accountid = @Id";
+            var parameterTypes = new Dictionary<string, DataTypeReference>
+            {
+                ["@Id"] = DataTypeHelpers.UniqueIdentifier
+            };
+            var plans = planBuilder.Build(query, parameterTypes, out _);
+
+            Assert.AreEqual(1, plans.Length);
+
+            var delete = AssertNode<DeleteNode>(plans[0]);
+            var constant = AssertNode<ConstantScanNode>(delete.Source);
+        }
+
+        [TestMethod]
+        public void DeleteByNameDoesNotUseConstantScan()
+        {
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
+
+            var query = "DELETE FROM account WHERE name = 'Data8'";
+
+            var plans = planBuilder.Build(query, null, out _);
+
+            Assert.AreEqual(1, plans.Length);
+
+            var delete = AssertNode<DeleteNode>(plans[0]);
+            var fetch = AssertNode<FetchXmlScan>(delete.Source);
+        }
+
+        [TestMethod]
+        public void UpdateByIdUsesConstantScan()
+        {
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
+
+            var query = "UPDATE account SET name = 'test' WHERE accountid = '1D3AACA6-DEA4-490F-973E-E4181D4BE11C'";
+
+            var plans = planBuilder.Build(query, null, out _);
+
+            Assert.AreEqual(1, plans.Length);
+
+            var update = AssertNode<UpdateNode>(plans[0]);
+            var computeScalar = AssertNode<ComputeScalarNode>(update.Source);
+            var constant = AssertNode<ConstantScanNode>(computeScalar.Source);
+        }
+
+        [TestMethod]
+        public void UpdateByIdCopyingFieldUsesConstantScan()
+        {
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
+
+            var query = "UPDATE account SET name = owneridname WHERE accountid = '1D3AACA6-DEA4-490F-973E-E4181D4BE11C'";
+
+            var plans = planBuilder.Build(query, null, out _);
+
+            Assert.AreEqual(1, plans.Length);
+
+            var update = AssertNode<UpdateNode>(plans[0]);
+            var fetch = AssertNode<FetchXmlScan>(update.Source);
+        }
+
+        [TestMethod]
+        public void InVariables()
+        {
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
+
+            var query = "SELECT name FROM account WHERE accountid IN (@Id1, @Id2)";
+            var parameterTypes = new Dictionary<string, DataTypeReference>
+            {
+                ["@Id1"] = DataTypeHelpers.UniqueIdentifier,
+                ["@Id2"] = DataTypeHelpers.UniqueIdentifier
+            };
+
+            var plans = planBuilder.Build(query, parameterTypes, out _);
+
+            Assert.AreEqual(1, plans.Length);
+
+            var select = AssertNode<SelectNode>(plans[0]);
+            var fetch = AssertNode<FetchXmlScan>(select.Source);
+            AssertFetchXml(fetch, @"
+<fetch xmlns:generator='MarkMpn.SQL4CDS'>
+    <entity name='account'>
+        <attribute name='name' />
+        <filter>
+            <condition attribute='accountid' operator='in'>
+                <value generator:IsVariable='true'>@Id1</value>
+                <value generator:IsVariable='true'>@Id2</value>
+            </condition>
+        </filter>
+    </entity>
 </fetch>");
         }
     }
diff --git a/MarkMpn.Sql4Cds.Engine.Tests/ExpressionFunctionTests.cs b/MarkMpn.Sql4Cds.Engine.Tests/ExpressionFunctionTests.cs
new file mode 100644
index 00000000..e47e72d0
--- /dev/null
+++ b/MarkMpn.Sql4Cds.Engine.Tests/ExpressionFunctionTests.cs
@@ -0,0 +1,362 @@
+using System;
+using System.Collections.Generic;
+using System.Data.SqlTypes;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using MarkMpn.Sql4Cds.Engine.ExecutionPlan;
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+
+namespace MarkMpn.Sql4Cds.Engine.Tests
+{
+    [TestClass]
+    public class ExpressionFunctionTests
+    {
+        [TestMethod]
+        public void DatePart_Week()
+        {
+            // https://learn.microsoft.com/en-us/sql/t-sql/functions/datepart-transact-sql?view=sql-server-ver16#week-and-weekday-datepart-arguments
+            // Assuming default SET DATEFIRST 7 -- ( Sunday )
+            var actual = ExpressionFunctions.DatePart("week", (SqlDateTime)new DateTime(2007, 4, 21), DataTypeHelpers.DateTime);
+            Assert.AreEqual(16, actual);
+        }
+
+        [TestMethod]
+        public void DatePart_WeekDay()
+        {
+            // https://learn.microsoft.com/en-us/sql/t-sql/functions/datepart-transact-sql?view=sql-server-ver16#week-and-weekday-datepart-arguments
+            // Assuming default SET DATEFIRST 7 -- ( Sunday )
+            var actual = ExpressionFunctions.DatePart("weekday", (SqlDateTime)new DateTime(2007, 4, 21), DataTypeHelpers.DateTime);
+            Assert.AreEqual(7, actual);
+        }
+
+        [TestMethod]
+        public void DatePart_TZOffset()
+        {
+            // https://learn.microsoft.com/en-us/sql/t-sql/functions/datepart-transact-sql?view=sql-server-ver16#tzoffset
+            var actual = ExpressionFunctions.DatePart("tzoffset", (SqlDateTimeOffset)new DateTimeOffset(2007, 5, 10, 0, 0, 1, TimeSpan.FromMinutes(5 * 60 + 10)), DataTypeHelpers.DateTimeOffset(7));
+            Assert.AreEqual(310, actual);
+        }
+
+        [TestMethod]
+        public void DatePart_ErrorOnInvalidPartsForTimeValue()
+        {
+            // https://learn.microsoft.com/en-us/sql/t-sql/functions/datepart-transact-sql?view=sql-server-ver16#default-returned-for-a-datepart-that-isnt-in-a-date-argument
+            try
+            {
+                ExpressionFunctions.DatePart("year", new SqlTime(new TimeSpan(0, 12, 10, 30, 123)), DataTypeHelpers.Time(7));
+                Assert.Fail();
+            }
+            catch (QueryExecutionException ex)
+            {
+                Assert.AreEqual(9810, ex.Errors.Single().Number);
+            }
+        }
+
+        [DataTestMethod]
+        [DataRow("millisecond", 123)]
+        [DataRow("microsecond", 123456)]
+        [DataRow("nanosecond", 123456700)]
+        public void DatePart_FractionalSeconds(string part, int expected)
+        {
+            // https://learn.microsoft.com/en-us/sql/t-sql/functions/datepart-transact-sql?view=sql-server-ver16#fractional-seconds
+            var actual = ExpressionFunctions.DatePart(part, (SqlString)"00:00:01.1234567", DataTypeHelpers.VarChar(100, Collation.USEnglish, CollationLabel.CoercibleDefault));
+            Assert.AreEqual(expected, actual);
+        }
+
+        [DataTestMethod]
+        [DataRow("20240830")]
+        [DataRow("2024-08-31")]
+        public void DateAdd_MonthLimitedToDaysInFollowingMonth(string date)
+        {
+            // https://learn.microsoft.com/en-us/sql/t-sql/functions/dateadd-transact-sql?view=sql-server-ver16#datepart-argument
+            SqlDateParsing.TryParse(date, DateFormat.mdy, out SqlDateTime startDate);
+            var actual = ExpressionFunctions.DateAdd("month", 1, startDate, DataTypeHelpers.DateTime);
+            Assert.AreEqual(new SqlDateTime(2024, 9, 30), (SqlDateTime)actual);
+        }
+
+        [DataTestMethod]
+        [DataRow(2147483647)]
+        [DataRow(-2147483647)]
+        public void DateAdd_ThrowsIfResultIsOutOfRange(int number)
+        {
+            // https://learn.microsoft.com/en-us/sql/t-sql/functions/dateadd-transact-sql?view=sql-server-ver16#date-argument
+            try
+            {
+                ExpressionFunctions.DateAdd("year", number, new SqlDateTime(2024, 7, 31), DataTypeHelpers.DateTime);
+            }
+            catch (QueryExecutionException ex)
+            {
+                Assert.AreEqual(517, ex.Errors.Single().Number);
+            }
+        }
+
+        [DataTestMethod]
+        [DataRow(-30, 0)]
+        [DataRow(29, 0)]
+        [DataRow(-31, -1)]
+        [DataRow(30, 1)]
+        public void DateAdd_SmallDateTimeSeconds(int number, int expectedMinutesDifference)
+        {
+            // https://learn.microsoft.com/en-us/sql/t-sql/functions/dateadd-transact-sql?view=sql-server-ver16#return-values-for-a-smalldatetime-date-and-a-second-or-fractional-seconds-datepart
+            var startDateTime = new DateTime(2024, 10, 5);
+            var actual = ((SqlSmallDateTime)ExpressionFunctions.DateAdd("second", number, new SqlSmallDateTime(startDateTime), DataTypeHelpers.SmallDateTime)).Value;
+            var expected = startDateTime.AddMinutes(expectedMinutesDifference);
+            Assert.AreEqual(expected, actual);
+        }
+
+        [DataTestMethod]
+        [DataRow(-30001, 0)]
+        [DataRow(29998, 0)]
+        [DataRow(-30002, -1)]
+        [DataRow(29999, 1)]
+        public void DateAdd_SmallDateTimeMilliSeconds(int number, int expectedMinutesDifference)
+        {
+            // https://learn.microsoft.com/en-us/sql/t-sql/functions/dateadd-transact-sql?view=sql-server-ver16#return-values-for-a-smalldatetime-date-and-a-second-or-fractional-seconds-datepart
+            var startDateTime = new DateTime(2024, 10, 5);
+            var actual = ((SqlSmallDateTime)ExpressionFunctions.DateAdd("millisecond", number, new SqlSmallDateTime(startDateTime), DataTypeHelpers.SmallDateTime)).Value;
+            var expected = startDateTime.AddMinutes(expectedMinutesDifference);
+            Assert.AreEqual(expected, actual);
+        }
+
+        [DataTestMethod]
+        [DataRow("millisecond", 1, 1121111)]
+        [DataRow("millisecond", 2, 1131111)]
+        [DataRow("microsecond", 1, 1111121)]
+        [DataRow("microsecond", 2, 1111131)]
+        [DataRow("nanosecond", 49, 1111111)]
+        [DataRow("nanosecond", 50, 1111112)]
+        [DataRow("nanosecond", 150, 1111113)]
+        public void DateAdd_FractionalSeconds(string datepart, int number, int expected)
+        {
+            // https://learn.microsoft.com/en-us/sql/t-sql/functions/dateadd-transact-sql?view=sql-server-ver16#fractional-seconds-precision
+            var startDateTime = new DateTime(2024, 1, 1, 13, 10, 10).AddTicks(1111111);
+            var actual = ExpressionFunctions.DateAdd(datepart, number, new SqlDateTime2(startDateTime), DataTypeHelpers.DateTime2(7)).Value;
+            Assert.AreEqual(expected, actual.Ticks % TimeSpan.TicksPerSecond);
+        }
+
+        [DataTestMethod]
+        [DataRow("year", "2025-01-01 13:10:10.1111111")]
+        [DataRow("quarter", "2024-04-01 13:10:10.1111111")]
+        [DataRow("month", "2024-02-01 13:10:10.1111111")]
+        [DataRow("dayofyear", "2024-01-02 13:10:10.1111111")]
+        [DataRow("day", "2024-01-02 13:10:10.1111111")]
+        [DataRow("week", "2024-01-08 13:10:10.1111111")]
+        [DataRow("weekday", "2024-01-02 13:10:10.1111111")]
+        [DataRow("hour", "2024-01-01 14:10:10.1111111")]
+        [DataRow("minute", "2024-01-01 13:11:10.1111111")]
+        [DataRow("second", "2024-01-01 13:10:11.1111111")]
+        [DataRow("millisecond", "2024-01-01 13:10:10.1121111")]
+        [DataRow("microsecond", "2024-01-01 13:10:10.1111121")]
+        [DataRow("nanosecond", "2024-01-01 13:10:10.1111111")]
+        public void DateAdd_DateParts(string datepart, string expected)
+        {
+            // https://learn.microsoft.com/en-us/sql/t-sql/functions/dateadd-transact-sql?view=sql-server-ver16#a-increment-datepart-by-an-interval-of-1
+            var startDateTime = new DateTime(2024, 1, 1, 13, 10, 10).AddTicks(1111111);
+            var actual = ExpressionFunctions.DateAdd(datepart, 1, new SqlDateTime2(startDateTime), DataTypeHelpers.DateTime2(7)).Value;
+            Assert.AreEqual(expected, actual.ToString("yyyy-MM-dd HH:mm:ss.fffffff"));
+        }
+
+        [DataTestMethod]
+        [DataRow("quarter", 4, "2025-01-01 01:01:01.1111111")]
+        [DataRow("month", 13, "2025-02-01 01:01:01.1111111")]
+        [DataRow("dayofyear", 366, "2025-01-01 01:01:01.1111111")] // NOTE: Docs used 365, but 2024 is a leap year
+        [DataRow("day", 366, "2025-01-01 01:01:01.1111111")] // NOTE: Docs used 365, but 2024 is a leap year
+        [DataRow("week", 5, "2024-02-05 01:01:01.1111111")]
+        [DataRow("weekday", 31, "2024-02-01 01:01:01.1111111")]
+        [DataRow("hour", 23, "2024-01-02 00:01:01.1111111")]
+        [DataRow("minute", 59, "2024-01-01 02:00:01.1111111")]
+        [DataRow("second", 59, "2024-01-01 01:02:00.1111111")]
+        [DataRow("millisecond", 1, "2024-01-01 01:01:01.1121111")]
+        public void DateAdd_Carry(string datepart, int number, string expected)
+        {
+            // https://learn.microsoft.com/en-us/sql/t-sql/functions/dateadd-transact-sql?view=sql-server-ver16#b-increment-more-than-one-level-of-datepart-in-one-statement
+            var startDateTime = new DateTime(2024, 1, 1, 1, 1, 1).AddTicks(1111111);
+            var actual = ExpressionFunctions.DateAdd(datepart, number, new SqlDateTime2(startDateTime), DataTypeHelpers.DateTime2(7)).Value;
+            Assert.AreEqual(expected, actual.ToString("yyyy-MM-dd HH:mm:ss.fffffff"));
+        }
+
+        [DataTestMethod]
+        [DataRow("microsecond")]
+        [DataRow("nanosecond")]
+        public void DateAdd_MicroSecondAndNanoSecondNotSupportedForSmallDateTime(string datepart)
+        {
+            // https://learn.microsoft.com/en-us/sql/t-sql/functions/dateadd-transact-sql?view=sql-server-ver16#fractional-seconds-precision
+            try
+            {
+                ExpressionFunctions.DateAdd(datepart, 1, new SqlSmallDateTime(new DateTime(2024, 1, 1)), DataTypeHelpers.SmallDateTime);
+                Assert.Fail();
+            }
+            catch (QueryExecutionException ex)
+            {
+                Assert.AreEqual(9810, ex.Errors.Single().Number);
+            }
+        }
+
+        [DataTestMethod]
+        [DataRow("microsecond")]
+        [DataRow("nanosecond")]
+        public void DateAdd_MicroSecondAndNanoSecondNotSupportedForDate(string datepart)
+        {
+            // https://learn.microsoft.com/en-us/sql/t-sql/functions/dateadd-transact-sql?view=sql-server-ver16#fractional-seconds-precision
+            try
+            {
+                ExpressionFunctions.DateAdd(datepart, 1, new SqlDate(new DateTime(2024, 1, 1)), DataTypeHelpers.Date);
+                Assert.Fail();
+            }
+            catch (QueryExecutionException ex)
+            {
+                Assert.AreEqual(9810, ex.Errors.Single().Number);
+            }
+        }
+
+        [DataTestMethod]
+        [DataRow("microsecond")]
+        [DataRow("nanosecond")]
+        public void DateAdd_MicroSecondAndNanoSecondNotSupportedForDateTime(string datepart)
+        {
+            // https://learn.microsoft.com/en-us/sql/t-sql/functions/dateadd-transact-sql?view=sql-server-ver16#fractional-seconds-precision
+            try
+            {
+                ExpressionFunctions.DateAdd(datepart, 1, new SqlDateTime(new DateTime(2024, 1, 1)), DataTypeHelpers.DateTime);
+                Assert.Fail();
+            }
+            catch (QueryExecutionException ex)
+            {
+                Assert.AreEqual(9810, ex.Errors.Single().Number);
+            }
+        }
+
+        [DataTestMethod]
+        [DataRow("weekday")]
+        [DataRow("tzoffset")]
+        [DataRow("nanosecond")]
+        public void DateTrunc_InvalidDateParts(string datepart)
+        {
+            // https://learn.microsoft.com/en-us/sql/t-sql/functions/datetrunc-transact-sql?view=sql-server-ver16#datepart
+            try
+            {
+                ExpressionFunctions.DateTrunc(datepart, new SqlDateTime(new DateTime(2024, 1, 1)), DataTypeHelpers.DateTime);
+                Assert.Fail();
+            }
+            catch (QueryExecutionException ex)
+            {
+                Assert.AreEqual(9810, ex.Errors.Single().Number);
+            }
+        }
+
+        [DataTestMethod]
+        // date doesn't support any of the time-based dateparts
+        [DataRow("date", "hour")]
+        [DataRow("date", "minute")]
+        [DataRow("date", "second")]
+        [DataRow("date", "millisecond")]
+        [DataRow("date", "microsecond")]
+
+        // datetime doesn't support microsecond
+        [DataRow("datetime", "microsecond")]
+
+        // smalldatetime doesn't support millisecond or microsecond
+        [DataRow("smalldatetime", "millisecond")]
+        [DataRow("smalldatetime", "microsecond")]
+
+        // datetime2, datetimeoffset and time vary depending on scale
+        [DataRow("datetime2(1)", "millisecond")]
+        [DataRow("datetime2(1)", "microsecond")]
+        [DataRow("datetime2(2)", "millisecond")]
+        [DataRow("datetime2(2)", "microsecond")]
+        [DataRow("datetime2(3)", "microsecond")]
+        [DataRow("datetime2(4)", "microsecond")]
+        [DataRow("datetime2(5)", "microsecond")]
+
+        [DataRow("datetimeoffset(1)", "millisecond")]
+        [DataRow("datetimeoffset(1)", "microsecond")]
+        [DataRow("datetimeoffset(2)", "millisecond")]
+        [DataRow("datetimeoffset(2)", "microsecond")]
+        [DataRow("datetimeoffset(3)", "microsecond")]
+        [DataRow("datetimeoffset(4)", "microsecond")]
+        [DataRow("datetimeoffset(5)", "microsecond")]
+
+        [DataRow("time(1)", "millisecond")]
+        [DataRow("time(1)", "microsecond")]
+        [DataRow("time(2)", "millisecond")]
+        [DataRow("time(2)", "microsecond")]
+        [DataRow("time(3)", "microsecond")]
+        [DataRow("time(4)", "microsecond")]
+        [DataRow("time(5)", "microsecond")]
+
+        // time also doesn't support any date-based dateparts
+        [DataRow("time", "year")]
+        [DataRow("time", "quarter")]
+        [DataRow("time", "month")]
+        [DataRow("time", "dayofyear")]
+        [DataRow("time", "day")]
+        [DataRow("time", "week")]
+        public void DateTrunc_RequiresMinimalPrecision(string datetype, string datepart)
+        {
+            DataTypeHelpers.TryParse(null, datetype, out var type);
+
+            // https://learn.microsoft.com/en-us/sql/t-sql/functions/datetrunc-transact-sql?view=sql-server-ver16#fractional-time-scale-precision
+            try
+            {
+                ExpressionFunctions.DateTrunc(datepart, new SqlDateTime(new DateTime(2024, 1, 1)), type);
+                Assert.Fail();
+            }
+            catch (QueryExecutionException ex)
+            {
+                Assert.AreEqual(9810, ex.Errors.Single().Number);
+            }
+        }
+
+        [DataTestMethod]
+        [DataRow("year", "2021-01-01 00:00:00.0000000")]
+        [DataRow("quarter", "2021-10-01 00:00:00.0000000")]
+        [DataRow("month", "2021-12-01 00:00:00.0000000")]
+        [DataRow("week", "2021-12-05 00:00:00.0000000")]
+        [DataRow("iso_week", "2021-12-06 00:00:00.0000000")]
+        [DataRow("dayofyear", "2021-12-08 00:00:00.0000000")]
+        [DataRow("day", "2021-12-08 00:00:00.0000000")]
+        [DataRow("hour", "2021-12-08 11:00:00.0000000")]
+        [DataRow("minute", "2021-12-08 11:30:00.0000000")]
+        [DataRow("second", "2021-12-08 11:30:15.0000000")]
+        [DataRow("millisecond", "2021-12-08 11:30:15.1230000")]
+        [DataRow("microsecond", "2021-12-08 11:30:15.1234560")]
+        public void DateTrunc_Values(string datepart, string expected)
+        {
+            // https://learn.microsoft.com/en-us/sql/t-sql/functions/datetrunc-transact-sql?view=sql-server-ver16#a-use-different-datepart-options
+            var actual = ExpressionFunctions.DateTrunc(datepart, new SqlDateTime2(new DateTime(2021, 12, 8, 11, 30, 15).AddTicks(1234567)), DataTypeHelpers.DateTime2(7));
+            Assert.AreEqual(expected, actual.Value.ToString("yyyy-MM-dd HH:mm:ss.fffffff"));
+        }
+
+        [DataTestMethod]
+        [DataRow("year", "2005-12-31 23:59:59.9999999", "2006-01-01 00:00:00.0000000")]
+        [DataRow("quarter", "2005-12-31 23:59:59.9999999", "2006-01-01 00:00:00.0000000")]
+        [DataRow("month", "2005-12-31 23:59:59.9999999", "2006-01-01 00:00:00.0000000")]
+        [DataRow("dayofyear", "2005-12-31 23:59:59.9999999", "2006-01-01 00:00:00.0000000")]
+        [DataRow("day", "2005-12-31 23:59:59.9999999", "2006-01-01 00:00:00.0000000")]
+        [DataRow("week", "2005-12-31 23:59:59.9999999", "2006-01-01 00:00:00.0000000")]
+        [DataRow("weekday", "2005-12-31 23:59:59.9999999", "2006-01-01 00:00:00.0000000")]
+        [DataRow("hour", "2005-12-31 23:59:59.9999999", "2006-01-01 00:00:00.0000000")]
+        [DataRow("minute", "2005-12-31 23:59:59.9999999", "2006-01-01 00:00:00.0000000")]
+        [DataRow("second", "2005-12-31 23:59:59.9999999", "2006-01-01 00:00:00.0000000")]
+        [DataRow("millisecond", "2005-12-31 23:59:59.9999999", "2006-01-01 00:00:00.0000000")]
+        [DataRow("microsecond", "2005-12-31 23:59:59.9999999", "2006-01-01 00:00:00.0000000")]
+        public void DateDiff_1Boundary(string datepart, string startdate, string enddate)
+        {
+            // https://learn.microsoft.com/en-us/sql/t-sql/functions/datediff-transact-sql?view=sql-server-ver16#datepart-boundaries
+            SqlDateParsing.TryParse(startdate, DateFormat.mdy, out SqlDateTimeOffset start);
+            SqlDateParsing.TryParse(enddate, DateFormat.mdy, out SqlDateTimeOffset end);
+            var actual = ExpressionFunctions.DateDiff(datepart, start, end, DataTypeHelpers.DateTimeOffset(7), DataTypeHelpers.DateTimeOffset(7));
+            Assert.AreEqual(1, actual);
+        }
+
+        [TestMethod]
+        public void DateDiff_TimeZone()
+        {
+            var dateTime = new DateTime(2024, 10, 5, 12, 0, 0);
+            var offset = new DateTimeOffset(dateTime, TimeSpan.FromHours(1));
+            var actual = ExpressionFunctions.DateDiff("hour", new SqlDateTime(dateTime), new SqlDateTimeOffset(offset), DataTypeHelpers.DateTime, DataTypeHelpers.DateTimeOffset(7));
+            Assert.AreEqual(-1, actual);
+        }
+    }
+}
diff --git a/MarkMpn.Sql4Cds.Engine.Tests/ExpressionTests.cs b/MarkMpn.Sql4Cds.Engine.Tests/ExpressionTests.cs
index ff6c0273..1d13faec 100644
--- a/MarkMpn.Sql4Cds.Engine.Tests/ExpressionTests.cs
+++ b/MarkMpn.Sql4Cds.Engine.Tests/ExpressionTests.cs
@@ -23,7 +23,7 @@ public void StringLiteral()
             var schema = new NodeSchema(new Dictionary<string, IColumnDefinition>(), new Dictionary<string, IReadOnlyList<string>>(), null, Array.Empty<string>());
             var parameterTypes = new Dictionary<string, DataTypeReference>();
             var options = new StubOptions();
-            var compilationContext = new ExpressionCompilationContext(_localDataSources, options, parameterTypes, schema, null);
+            var compilationContext = new ExpressionCompilationContext(new SessionContext(_localDataSources, options), options, parameterTypes, schema, null);
             var func = expr.Compile(compilationContext);
 
             var actual = func(new ExpressionExecutionContext(compilationContext));
@@ -40,7 +40,7 @@ public void IntegerLiteral()
             var schema = new NodeSchema(new Dictionary<string, IColumnDefinition>(), new Dictionary<string, IReadOnlyList<string>>(), null, Array.Empty<string>());
             var parameterTypes = new Dictionary<string, DataTypeReference>();
             var options = new StubOptions();
-            var compilationContext = new ExpressionCompilationContext(_localDataSources, options, parameterTypes, schema, null);
+            var compilationContext = new ExpressionCompilationContext(new SessionContext(_localDataSources, options), options, parameterTypes, schema, null);
             var func = expr.Compile(compilationContext);
 
             var actual = func(new ExpressionExecutionContext(compilationContext));
@@ -62,7 +62,7 @@ public void StringConcat()
             var schema = new NodeSchema(new Dictionary<string, IColumnDefinition>(), new Dictionary<string, IReadOnlyList<string>>(), null, Array.Empty<string>());
             var parameterTypes = new Dictionary<string, DataTypeReference>();
             var options = new StubOptions();
-            var compilationContext = new ExpressionCompilationContext(_localDataSources, options, parameterTypes, schema, null);
+            var compilationContext = new ExpressionCompilationContext(new SessionContext(_localDataSources, options), options, parameterTypes, schema, null);
             var func = expr.Compile(compilationContext);
 
             var actual = func(new ExpressionExecutionContext(compilationContext));
@@ -83,7 +83,7 @@ public void IntegerAddition()
             var schema = new NodeSchema(new Dictionary<string, IColumnDefinition>(), new Dictionary<string, IReadOnlyList<string>>(), null, Array.Empty<string>());
             var parameterTypes = new Dictionary<string, DataTypeReference>();
             var options = new StubOptions();
-            var compilationContext = new ExpressionCompilationContext(_localDataSources, options, parameterTypes, schema, null);
+            var compilationContext = new ExpressionCompilationContext(new SessionContext(_localDataSources, options), options, parameterTypes, schema, null);
             var func = expr.Compile(compilationContext);
 
             var actual = func(new ExpressionExecutionContext(compilationContext));
@@ -118,7 +118,7 @@ public void SimpleCaseExpression()
             }, new Dictionary<string, IReadOnlyList<string>>(), null, Array.Empty<string>());
             var parameterTypes = new Dictionary<string, DataTypeReference>();
             var options = new StubOptions();
-            var compilationContext = new ExpressionCompilationContext(_localDataSources, options, parameterTypes, schema, null);
+            var compilationContext = new ExpressionCompilationContext(new SessionContext(_localDataSources, options), options, parameterTypes, schema, null);
             var func = expr.Compile(compilationContext);
 
             var record = new Entity
@@ -158,7 +158,7 @@ public void FormatDateTime()
             }, new Dictionary<string, IReadOnlyList<string>>(), null, Array.Empty<string>());
             var parameterTypes = new Dictionary<string, DataTypeReference>();
             var options = new StubOptions();
-            var compilationContext = new ExpressionCompilationContext(_localDataSources, options, parameterTypes, schema, null);
+            var compilationContext = new ExpressionCompilationContext(new SessionContext(_localDataSources, options), options, parameterTypes, schema, null);
             var func = expr.Compile(compilationContext);
 
             var record = new Entity
@@ -186,7 +186,7 @@ public void LikeWithEmbeddedReturns()
             }, new Dictionary<string, IReadOnlyList<string>>(), null, Array.Empty<string>());
             var parameterTypes = new Dictionary<string, DataTypeReference>();
             var options = new StubOptions();
-            var compilationContext = new ExpressionCompilationContext(_localDataSources, options, parameterTypes, schema, null);
+            var compilationContext = new ExpressionCompilationContext(new SessionContext(_localDataSources, options), options, parameterTypes, schema, null);
             var func = expr.Compile(compilationContext);
 
             var record = new Entity
diff --git a/MarkMpn.Sql4Cds.Engine.Tests/MarkMpn.Sql4Cds.Engine.Tests.csproj b/MarkMpn.Sql4Cds.Engine.Tests/MarkMpn.Sql4Cds.Engine.Tests.csproj
index 04f7900c..3124265e 100644
--- a/MarkMpn.Sql4Cds.Engine.Tests/MarkMpn.Sql4Cds.Engine.Tests.csproj
+++ b/MarkMpn.Sql4Cds.Engine.Tests/MarkMpn.Sql4Cds.Engine.Tests.csproj
@@ -77,9 +77,11 @@
   </ItemGroup>
   <ItemGroup>
     <Compile Include="CollationTests.cs" />
+    <Compile Include="SqlDateTests.cs" />
     <Compile Include="ExecutionPlanNodeTests.cs" />
     <Compile Include="CteTests.cs" />
     <Compile Include="ExecutionPlanTests.cs" />
+    <Compile Include="ExpressionFunctionTests.cs" />
     <Compile Include="ExpressionTests.cs" />
     <Compile Include="FakeXrmDataSource.cs" />
     <Compile Include="FakeXrmEasyTestsBase.cs" />
@@ -101,6 +103,8 @@
     <Compile Include="SampleMessageExecutor.cs" />
     <Compile Include="Sql2FetchXmlTests.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
+    <Compile Include="SqlDateTimeTests.cs" />
+    <Compile Include="SqlTimeTests.cs" />
     <Compile Include="SqlVariantTests.cs" />
     <Compile Include="StringSplitTests.cs" />
     <Compile Include="StubOptions.cs" />
diff --git a/MarkMpn.Sql4Cds.Engine.Tests/OptionsWrapper.cs b/MarkMpn.Sql4Cds.Engine.Tests/OptionsWrapper.cs
index ac29f142..76db91da 100644
--- a/MarkMpn.Sql4Cds.Engine.Tests/OptionsWrapper.cs
+++ b/MarkMpn.Sql4Cds.Engine.Tests/OptionsWrapper.cs
@@ -60,6 +60,19 @@ public OptionsWrapper(IQueryExecutionOptions options)
 
         public ColumnOrdering ColumnOrdering { get; set; }
 
+        public event EventHandler PrimaryDataSourceChanged
+        {
+            add
+            {
+                _options.PrimaryDataSourceChanged += value;
+            }
+
+            remove
+            {
+                _options.PrimaryDataSourceChanged -= value;
+            }
+        }
+
         public void ConfirmDelete(ConfirmDmlStatementEventArgs e)
         {
         }
diff --git a/MarkMpn.Sql4Cds.Engine.Tests/Sql2FetchXmlTests.cs b/MarkMpn.Sql4Cds.Engine.Tests/Sql2FetchXmlTests.cs
index 99b7dd18..b1d3ef78 100644
--- a/MarkMpn.Sql4Cds.Engine.Tests/Sql2FetchXmlTests.cs
+++ b/MarkMpn.Sql4Cds.Engine.Tests/Sql2FetchXmlTests.cs
@@ -54,12 +54,14 @@ public class Sql2FetchXmlTests : FakeXrmEasyTestsBase, IQueryExecutionOptions
 
         ColumnOrdering IQueryExecutionOptions.ColumnOrdering => ColumnOrdering.Alphabetical;
 
+        public event EventHandler PrimaryDataSourceChanged;
+
         [TestMethod]
         public void SimpleSelect()
         {
             var query = "SELECT accountid, name FROM account";
 
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
             var queries = planBuilder.Build(query, null, out _);
 
             AssertFetchXml(queries, @"
@@ -77,7 +79,7 @@ public void SelectSameFieldMultipleTimes()
         {
             var query = "SELECT accountid, name, name FROM account";
 
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
             var queries = planBuilder.Build(query, null, out _);
 
             AssertFetchXml(queries, @"
@@ -102,7 +104,7 @@ public void SelectStar()
         {
             var query = "SELECT * FROM account";
 
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
             var queries = planBuilder.Build(query, null, out _);
 
             AssertFetchXml(queries, @"
@@ -135,7 +137,7 @@ public void SelectStarAndField()
         {
             var query = "SELECT *, name FROM account";
 
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
             var queries = planBuilder.Build(query, null, out _);
 
             AssertFetchXml(queries, @"
@@ -169,7 +171,7 @@ public void SimpleFilter()
         {
             var query = "SELECT accountid, name FROM account WHERE name = 'test'";
 
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
             var queries = planBuilder.Build(query, null, out _);
 
             AssertFetchXml(queries, @"
@@ -190,7 +192,7 @@ public void BetweenFilter()
         {
             var query = "SELECT accountid, name FROM account WHERE employees BETWEEN 1 AND 10 AND turnover NOT BETWEEN 2 AND 20";
 
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
             var queries = planBuilder.Build(query, null, out _);
 
             AssertFetchXml(queries, @"
@@ -216,7 +218,7 @@ public void FetchFilter()
         {
             var query = "SELECT contactid, firstname FROM contact WHERE createdon = lastxdays(7)";
 
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
             var queries = planBuilder.Build(query, null, out _);
 
             AssertFetchXml(queries, @"
@@ -237,7 +239,7 @@ public void NestedFilters()
         {
             var query = "SELECT accountid, name FROM account WHERE name = 'test' OR (employees is not null and name like 'foo%')";
 
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
             var queries = planBuilder.Build(query, null, out _);
 
             AssertFetchXml(queries, @"
@@ -262,7 +264,7 @@ public void Sorts()
         {
             var query = "SELECT accountid, name FROM account ORDER BY name DESC, accountid";
 
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
             var queries = planBuilder.Build(query, null, out _);
 
             AssertFetchXml(queries, @"
@@ -282,7 +284,7 @@ public void SortByColumnIndex()
         {
             var query = "SELECT accountid, name FROM account ORDER BY 2 DESC, 1";
 
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
             var queries = planBuilder.Build(query, null, out _);
 
             AssertFetchXml(queries, @"
@@ -302,7 +304,7 @@ public void SortByAliasedColumn()
         {
             var query = "SELECT accountid, name as accountname FROM account ORDER BY name";
 
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
             var queries = planBuilder.Build(query, null, out _);
 
             AssertFetchXml(queries, @"
@@ -321,7 +323,7 @@ public void Top()
         {
             var query = "SELECT TOP 10 accountid, name FROM account";
 
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
             var queries = planBuilder.Build(query, null, out _);
 
             AssertFetchXml(queries, @"
@@ -339,7 +341,7 @@ public void TopBrackets()
         {
             var query = "SELECT TOP (10) accountid, name FROM account";
 
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
             var queries = planBuilder.Build(query, null, out _);
 
             AssertFetchXml(queries, @"
@@ -357,7 +359,7 @@ public void Top10KUsesExtension()
         {
             var query = "SELECT TOP 10000 accountid, name FROM account";
 
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
             var queries = planBuilder.Build(query, null, out _);
 
             AssertFetchXml(queries, @"
@@ -378,7 +380,7 @@ public void NoLock()
         {
             var query = "SELECT accountid, name FROM account (NOLOCK)";
 
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
             var queries = planBuilder.Build(query, null, out _);
 
             AssertFetchXml(queries, @"
@@ -396,7 +398,7 @@ public void Distinct()
         {
             var query = "SELECT DISTINCT name FROM account";
 
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
             var queries = planBuilder.Build(query, null, out _);
 
             AssertFetchXml(queries, @"
@@ -414,7 +416,7 @@ public void Offset()
         {
             var query = "SELECT accountid, name FROM account ORDER BY name OFFSET 100 ROWS FETCH NEXT 50 ROWS ONLY";
 
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
             var queries = planBuilder.Build(query, null, out _);
 
             AssertFetchXml(queries, @"
@@ -433,7 +435,7 @@ public void SimpleJoin()
         {
             var query = "SELECT accountid, name FROM account INNER JOIN contact ON primarycontactid = contactid";
 
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
             var queries = planBuilder.Build(query, null, out _);
 
             AssertFetchXml(queries, @"
@@ -453,7 +455,7 @@ public void SelfReferentialJoin()
         {
             var query = "SELECT contact.contactid, contact.firstname, manager.firstname FROM contact LEFT OUTER JOIN contact AS manager ON contact.parentcustomerid = manager.contactid";
 
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
             var queries = planBuilder.Build(query, null, out _);
 
             AssertFetchXml(queries, @"
@@ -474,7 +476,7 @@ public void AdditionalJoinCriteria()
         {
             var query = "SELECT accountid, name FROM account INNER JOIN contact ON accountid = parentcustomerid AND (firstname = 'Mark' OR lastname = 'Carrington')";
 
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
             var queries = planBuilder.Build(query, null, out _);
 
             AssertFetchXml(queries, @"
@@ -498,7 +500,7 @@ public void InvalidAdditionalJoinCriteria()
         {
             var query = "SELECT accountid, name FROM account INNER JOIN contact ON accountid = parentcustomerid OR (firstname = 'Mark' AND lastname = 'Carrington')";
 
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
             var queries = planBuilder.Build(query, null, out _);
 
             Assert.IsNotInstanceOfType(((SelectNode)queries[0]).Source, typeof(FetchXmlScan));
@@ -509,7 +511,7 @@ public void SortOnLinkEntity()
         {
             var query = "SELECT TOP 100 accountid, name FROM account INNER JOIN contact ON primarycontactid = contactid ORDER BY name, firstname";
 
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
             var queries = planBuilder.Build(query, null, out _);
 
             AssertFetchXml(queries, @"
@@ -531,7 +533,7 @@ public void InvalidSortOnLinkEntity()
         {
             var query = "SELECT TOP 100 accountid, name FROM account INNER JOIN contact ON accountid = parentcustomerid ORDER BY name, firstname";
 
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
             var queries = planBuilder.Build(query, null, out _);
 
             AssertFetchXml(queries, @"
@@ -558,7 +560,7 @@ public void SimpleAggregate()
         {
             var query = "SELECT count(*), count(name), count(DISTINCT name), max(name), min(name), avg(employees) FROM account";
 
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
             var queries = planBuilder.Build(query, null, out _);
 
             AssertFetchXml(queries, @"
@@ -580,7 +582,7 @@ public void GroupBy()
         {
             var query = "SELECT name, count(*) FROM account GROUP BY name";
 
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
             var queries = planBuilder.Build(query, null, out _);
 
             AssertFetchXml(queries, @"
@@ -599,7 +601,7 @@ public void GroupBySorting()
         {
             var query = "SELECT name, count(*) FROM account GROUP BY name ORDER BY name, count(*)";
 
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
             var queries = planBuilder.Build(query, null, out _);
 
             AssertFetchXml(queries, @"
@@ -619,7 +621,7 @@ public void GroupBySortingOnLinkEntity()
         {
             var query = "SELECT name, firstname, count(*) FROM account INNER JOIN contact ON parentcustomerid = account.accountid GROUP BY name, firstname ORDER BY firstname, name";
 
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
             var queries = planBuilder.Build(query, null, out _);
 
             AssertFetchXml(queries, @"
@@ -642,7 +644,7 @@ public void GroupBySortingOnAliasedAggregate()
         {
             var query = "SELECT name, firstname, count(*) as count FROM account INNER JOIN contact ON parentcustomerid = account.accountid GROUP BY name, firstname ORDER BY count";
 
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
             var queries = planBuilder.Build(query, null, out _);
 
             AssertFetchXml(queries, @"
@@ -664,7 +666,7 @@ public void UpdateFieldToValue()
         {
             var query = "UPDATE contact SET firstname = 'Mark'";
 
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
             var queries = planBuilder.Build(query, null, out _);
 
             AssertFetchXml(queries, @"
@@ -681,7 +683,7 @@ public void SelectArithmetic()
         {
             var query = "SELECT employees + 1 AS a, employees * 2 AS b, turnover / 3 AS c, turnover - 4 AS d, turnover / employees AS e FROM account";
 
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
             var queries = planBuilder.Build(query, null, out _);
 
             AssertFetchXml(queries, @"
@@ -704,7 +706,7 @@ public void SelectArithmetic()
                 }
             };
 
-            var dataReader = ((SelectNode)queries[0]).Execute(new NodeExecutionContext(GetDataSources(_context), this, new Dictionary<string, DataTypeReference>(), new Dictionary<string, INullable>(), null), CommandBehavior.Default);
+            var dataReader = ((SelectNode)queries[0]).Execute(new NodeExecutionContext(new SessionContext(GetDataSources(_context), this), this, new Dictionary<string, DataTypeReference>(), new Dictionary<string, INullable>(), null), CommandBehavior.Default);
             var dataTable = new DataTable();
             dataTable.Load(dataReader);
 
@@ -723,7 +725,7 @@ public void WhereComparingTwoFields()
             {
                 var query = "SELECT contactid FROM contact WHERE firstname = lastname";
 
-                var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+                var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
                 var queries = planBuilder.Build(query, null, out _);
 
                 AssertFetchXml(queries, @"
@@ -754,7 +756,7 @@ public void WhereComparingTwoFields()
                     }
                 };
 
-                var dataReader = ((SelectNode)queries[0]).Execute(new NodeExecutionContext(GetDataSources(_context), this, new Dictionary<string, DataTypeReference>(), new Dictionary<string, INullable>(), null), CommandBehavior.Default);
+                var dataReader = ((SelectNode)queries[0]).Execute(new NodeExecutionContext(new SessionContext(GetDataSources(_context), this), this, new Dictionary<string, DataTypeReference>(), new Dictionary<string, INullable>(), null), CommandBehavior.Default);
                 var dataTable = new DataTable();
                 dataTable.Load(dataReader);
 
@@ -768,7 +770,7 @@ public void WhereComparingExpression()
         {
             var query = "SELECT contactid FROM contact WHERE lastname = firstname + 'rington'";
 
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
             var queries = planBuilder.Build(query, null, out _);
 
             AssertFetchXml(queries, @"
@@ -799,7 +801,7 @@ public void WhereComparingExpression()
                 }
             };
 
-            var dataReader = ((SelectNode)queries[0]).Execute(new NodeExecutionContext(GetDataSources(_context), this, new Dictionary<string, DataTypeReference>(), new Dictionary<string, INullable>(), null), CommandBehavior.Default);
+            var dataReader = ((SelectNode)queries[0]).Execute(new NodeExecutionContext(new SessionContext(GetDataSources(_context), this), this, new Dictionary<string, DataTypeReference>(), new Dictionary<string, INullable>(), null), CommandBehavior.Default);
             var dataTable = new DataTable();
             dataTable.Load(dataReader);
 
@@ -812,7 +814,7 @@ public void BackToFrontLikeExpression()
         {
             var query = "SELECT contactid FROM contact WHERE 'Mark' like firstname";
 
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
             var queries = planBuilder.Build(query, null, out _);
 
             AssertFetchXml(queries, @"
@@ -840,7 +842,7 @@ public void BackToFrontLikeExpression()
                 }
             };
 
-            var dataReader = ((SelectNode)queries[0]).Execute(new NodeExecutionContext(GetDataSources(_context), this, new Dictionary<string, DataTypeReference>(), new Dictionary<string, INullable>(), null), CommandBehavior.Default);
+            var dataReader = ((SelectNode)queries[0]).Execute(new NodeExecutionContext(new SessionContext(GetDataSources(_context), this), this, new Dictionary<string, DataTypeReference>(), new Dictionary<string, INullable>(), null), CommandBehavior.Default);
             var dataTable = new DataTable();
             dataTable.Load(dataReader);
 
@@ -853,7 +855,7 @@ public void UpdateFieldToField()
         {
             var query = "UPDATE contact SET firstname = lastname";
 
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
             var queries = planBuilder.Build(query, null, out _);
 
             AssertFetchXml(queries, @"
@@ -875,7 +877,7 @@ public void UpdateFieldToField()
                 }
             };
 
-            ((UpdateNode)queries[0]).Execute(new NodeExecutionContext(GetDataSources(_context), this, new Dictionary<string, DataTypeReference>(), new Dictionary<string, INullable>(), null), out _, out _);
+            ((UpdateNode)queries[0]).Execute(new NodeExecutionContext(new SessionContext(GetDataSources(_context), this), this, new Dictionary<string, DataTypeReference>(), new Dictionary<string, INullable>(), null), out _, out _);
 
             Assert.AreEqual("Carrington", _context.Data["contact"][guid]["firstname"]);
         }
@@ -885,7 +887,7 @@ public void UpdateFieldToExpression()
         {
             var query = "UPDATE contact SET firstname = 'Hello ' + lastname";
 
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
             var queries = planBuilder.Build(query, null, out _);
 
             AssertFetchXml(queries, @"
@@ -907,7 +909,7 @@ public void UpdateFieldToExpression()
                 }
             };
 
-            ((UpdateNode)queries[0]).Execute(new NodeExecutionContext(GetDataSources(_context), this, new Dictionary<string, DataTypeReference>(), new Dictionary<string, INullable>(), null), out _, out _);
+            ((UpdateNode)queries[0]).Execute(new NodeExecutionContext(new SessionContext(GetDataSources(_context), this), this, new Dictionary<string, DataTypeReference>(), new Dictionary<string, INullable>(), null), out _, out _);
 
             Assert.AreEqual("Hello Carrington", _context.Data["contact"][guid]["firstname"]);
         }
@@ -917,7 +919,7 @@ public void UpdateReplace()
         {
             var query = "UPDATE contact SET firstname = REPLACE(firstname, 'Dataflex Pro', 'CDS') WHERE lastname = 'Carrington'";
 
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
             var queries = planBuilder.Build(query, null, out _);
 
             AssertFetchXml(queries, @"
@@ -943,7 +945,7 @@ public void UpdateReplace()
                 }
             };
 
-            ((UpdateNode)queries[0]).Execute(new NodeExecutionContext(GetDataSources(_context), this, new Dictionary<string, DataTypeReference>(), new Dictionary<string, INullable>(), null), out _, out _);
+            ((UpdateNode)queries[0]).Execute(new NodeExecutionContext(new SessionContext(GetDataSources(_context), this), this, new Dictionary<string, DataTypeReference>(), new Dictionary<string, INullable>(), null), out _, out _);
 
             Assert.AreEqual("--CDS--", _context.Data["contact"][guid]["firstname"]);
         }
@@ -953,7 +955,7 @@ public void StringFunctions()
         {
             var query = "SELECT trim(firstname) as trim, ltrim(firstname) as ltrim, rtrim(firstname) as rtrim, substring(firstname, 2, 3) as substring23, len(firstname) as len FROM contact";
 
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
             var queries = planBuilder.Build(query, null, out _);
 
             AssertFetchXml(queries, @"
@@ -974,7 +976,7 @@ public void StringFunctions()
                 }
             };
 
-            var dataReader = ((SelectNode)queries[0]).Execute(new NodeExecutionContext(GetDataSources(_context), this, new Dictionary<string, DataTypeReference>(), new Dictionary<string, INullable>(), null), CommandBehavior.Default);
+            var dataReader = ((SelectNode)queries[0]).Execute(new NodeExecutionContext(new SessionContext(GetDataSources(_context), this), this, new Dictionary<string, DataTypeReference>(), new Dictionary<string, INullable>(), null), CommandBehavior.Default);
             var dataTable = new DataTable();
             dataTable.Load(dataReader);
 
@@ -993,7 +995,7 @@ public void SelectExpression()
         {
             var query = "SELECT firstname, 'Hello ' + firstname AS greeting FROM contact";
 
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
             var queries = planBuilder.Build(query, null, out _);
 
             AssertFetchXml(queries, @"
@@ -1014,7 +1016,7 @@ public void SelectExpression()
                 }
             };
 
-            var dataReader = ((SelectNode)queries[0]).Execute(new NodeExecutionContext(GetDataSources(_context), this, new Dictionary<string, DataTypeReference>(), new Dictionary<string, INullable>(), null), CommandBehavior.Default);
+            var dataReader = ((SelectNode)queries[0]).Execute(new NodeExecutionContext(new SessionContext(GetDataSources(_context), this), this, new Dictionary<string, DataTypeReference>(), new Dictionary<string, INullable>(), null), CommandBehavior.Default);
             var dataTable = new DataTable();
             dataTable.Load(dataReader);
 
@@ -1043,7 +1045,7 @@ public void SelectExpressionNullValues()
         {
             var query = "SELECT firstname, 'Hello ' + firstname AS greeting, case when createdon > '2020-01-01' then 'new' else 'old' end AS age FROM contact";
 
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
             var queries = planBuilder.Build(query, null, out _);
 
             AssertFetchXml(queries, @"
@@ -1064,7 +1066,7 @@ public void SelectExpressionNullValues()
                 }
             };
 
-            var dataReader = ((SelectNode)queries[0]).Execute(new NodeExecutionContext(GetDataSources(_context), this, new Dictionary<string, DataTypeReference>(), new Dictionary<string, INullable>(), null), CommandBehavior.Default);
+            var dataReader = ((SelectNode)queries[0]).Execute(new NodeExecutionContext(new SessionContext(GetDataSources(_context), this), this, new Dictionary<string, DataTypeReference>(), new Dictionary<string, INullable>(), null), CommandBehavior.Default);
             var dataTable = new DataTable();
             dataTable.Load(dataReader);
 
@@ -1079,7 +1081,7 @@ public void OrderByExpression()
         {
             var query = "SELECT firstname, lastname FROM contact ORDER BY lastname + ', ' + firstname";
 
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
             var queries = planBuilder.Build(query, null, out _);
 
             AssertFetchXml(queries, @"
@@ -1109,7 +1111,7 @@ public void OrderByExpression()
                 }
             };
 
-            var dataReader = ((SelectNode)queries[0]).Execute(new NodeExecutionContext(GetDataSources(_context), this, new Dictionary<string, DataTypeReference>(), new Dictionary<string, INullable>(), null), CommandBehavior.Default);
+            var dataReader = ((SelectNode)queries[0]).Execute(new NodeExecutionContext(new SessionContext(GetDataSources(_context), this), this, new Dictionary<string, DataTypeReference>(), new Dictionary<string, INullable>(), null), CommandBehavior.Default);
             var dataTable = new DataTable();
             dataTable.Load(dataReader);
 
@@ -1123,7 +1125,7 @@ public void OrderByAliasedField()
         {
             var query = "SELECT firstname, lastname AS surname FROM contact ORDER BY surname";
 
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
             var queries = planBuilder.Build(query, null, out _);
 
             AssertFetchXml(queries, @"
@@ -1154,7 +1156,7 @@ public void OrderByAliasedField()
                 }
             };
 
-            var dataReader = ((SelectNode)queries[0]).Execute(new NodeExecutionContext(GetDataSources(_context), this, new Dictionary<string, DataTypeReference>(), new Dictionary<string, INullable>(), null), CommandBehavior.Default);
+            var dataReader = ((SelectNode)queries[0]).Execute(new NodeExecutionContext(new SessionContext(GetDataSources(_context), this), this, new Dictionary<string, DataTypeReference>(), new Dictionary<string, INullable>(), null), CommandBehavior.Default);
             var dataTable = new DataTable();
             dataTable.Load(dataReader);
 
@@ -1168,7 +1170,7 @@ public void OrderByCalculatedField()
         {
             var query = "SELECT firstname, lastname, lastname + ', ' + firstname AS fullname FROM contact ORDER BY fullname";
 
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
             var queries = planBuilder.Build(query, null, out _);
 
             AssertFetchXml(queries, @"
@@ -1198,7 +1200,7 @@ public void OrderByCalculatedField()
                 }
             };
 
-            var dataReader = ((SelectNode)queries[0]).Execute(new NodeExecutionContext(GetDataSources(_context), this, new Dictionary<string, DataTypeReference>(), new Dictionary<string, INullable>(), null), CommandBehavior.Default);
+            var dataReader = ((SelectNode)queries[0]).Execute(new NodeExecutionContext(new SessionContext(GetDataSources(_context), this), this, new Dictionary<string, DataTypeReference>(), new Dictionary<string, INullable>(), null), CommandBehavior.Default);
             var dataTable = new DataTable();
             dataTable.Load(dataReader);
 
@@ -1212,7 +1214,7 @@ public void OrderByCalculatedFieldByIndex()
         {
             var query = "SELECT firstname, lastname, lastname + ', ' + firstname AS fullname FROM contact ORDER BY 3";
 
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
             var queries = planBuilder.Build(query, null, out _);
 
             AssertFetchXml(queries, @"
@@ -1242,7 +1244,7 @@ public void OrderByCalculatedFieldByIndex()
                 }
             };
 
-            var dataReader = ((SelectNode)queries[0]).Execute(new NodeExecutionContext(GetDataSources(_context), this, new Dictionary<string, DataTypeReference>(), new Dictionary<string, INullable>(), null), CommandBehavior.Default);
+            var dataReader = ((SelectNode)queries[0]).Execute(new NodeExecutionContext(new SessionContext(GetDataSources(_context), this), this, new Dictionary<string, DataTypeReference>(), new Dictionary<string, INullable>(), null), CommandBehavior.Default);
             var dataTable = new DataTable();
             dataTable.Load(dataReader);
 
@@ -1256,7 +1258,7 @@ public void DateCalculations()
         {
             var query = "SELECT contactid, DATEADD(day, 1, createdon) AS nextday, DATEPART(minute, createdon) AS minute FROM contact WHERE DATEDIFF(hour, '2020-01-01', createdon) < 1";
 
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
             var queries = planBuilder.Build(query, null, out _);
 
             AssertFetchXml(queries, @"
@@ -1284,7 +1286,7 @@ public void DateCalculations()
                 }
             };
 
-            var dataReader = ((SelectNode)queries[0]).Execute(new NodeExecutionContext(GetDataSources(_context), this, new Dictionary<string, DataTypeReference>(), new Dictionary<string, INullable>(), null), CommandBehavior.Default);
+            var dataReader = ((SelectNode)queries[0]).Execute(new NodeExecutionContext(new SessionContext(GetDataSources(_context), this), this, new Dictionary<string, DataTypeReference>(), new Dictionary<string, INullable>(), null), CommandBehavior.Default);
             var dataTable = new DataTable();
             dataTable.Load(dataReader);
 
@@ -1301,7 +1303,7 @@ public void TopAppliedAfterCustomFilter()
             {
                 var query = "SELECT TOP 10 contactid FROM contact WHERE firstname = lastname";
 
-                var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+                var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
                 var queries = planBuilder.Build(query, null, out _);
 
                 AssertFetchXml(queries, @"
@@ -1324,7 +1326,7 @@ public void CustomFilterAggregateHavingProjectionSortAndTop()
         {
             var query = "SELECT TOP 10 lastname, SUM(CASE WHEN firstname = 'Mark' THEN 1 ELSE 0 END) as nummarks, LEFT(lastname, 1) AS lastinitial FROM contact WHERE DATEDIFF(day, '2020-01-01', createdon) > 10 GROUP BY lastname HAVING count(*) > 1 ORDER BY 2 DESC";
 
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
             var queries = planBuilder.Build(query, null, out _);
 
             AssertFetchXml(queries, @"
@@ -1372,7 +1374,7 @@ public void CustomFilterAggregateHavingProjectionSortAndTop()
                 }
             };
 
-            var dataReader = ((SelectNode)queries[0]).Execute(new NodeExecutionContext(GetDataSources(_context), this, new Dictionary<string, DataTypeReference>(), new Dictionary<string, INullable>(), null), CommandBehavior.Default);
+            var dataReader = ((SelectNode)queries[0]).Execute(new NodeExecutionContext(new SessionContext(GetDataSources(_context), this), this, new Dictionary<string, DataTypeReference>(), new Dictionary<string, INullable>(), null), CommandBehavior.Default);
             var dataTable = new DataTable();
             dataTable.Load(dataReader);
 
@@ -1392,7 +1394,7 @@ public void FilterCaseInsensitive()
         {
             var query = "SELECT contactid FROM contact WHERE DATEDIFF(day, '2020-01-01', createdon) < 10 OR lastname = 'Carrington' ORDER BY createdon";
 
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
             var queries = planBuilder.Build(query, null, out _);
 
             AssertFetchXml(queries, @"
@@ -1435,7 +1437,7 @@ public void FilterCaseInsensitive()
                 }
             };
 
-            var dataReader = ((SelectNode)queries[0]).Execute(new NodeExecutionContext(GetDataSources(_context), this, new Dictionary<string, DataTypeReference>(), new Dictionary<string, INullable>(), null), CommandBehavior.Default);
+            var dataReader = ((SelectNode)queries[0]).Execute(new NodeExecutionContext(new SessionContext(GetDataSources(_context), this), this, new Dictionary<string, DataTypeReference>(), new Dictionary<string, INullable>(), null), CommandBehavior.Default);
             var dataTable = new DataTable();
             dataTable.Load(dataReader);
 
@@ -1450,7 +1452,7 @@ public void GroupCaseInsensitive()
         {
             var query = "SELECT lastname, count(*) FROM contact WHERE DATEDIFF(day, '2020-01-01', createdon) > 10 GROUP BY lastname ORDER BY 2 DESC";
 
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
             var queries = planBuilder.Build(query, null, out _);
 
             AssertFetchXml(queries, @"
@@ -1492,7 +1494,7 @@ public void GroupCaseInsensitive()
                 }
             };
 
-            var dataReader = ((SelectNode)queries[0]).Execute(new NodeExecutionContext(GetDataSources(_context), this, new Dictionary<string, DataTypeReference>(), new Dictionary<string, INullable>(), null), CommandBehavior.Default);
+            var dataReader = ((SelectNode)queries[0]).Execute(new NodeExecutionContext(new SessionContext(GetDataSources(_context), this), this, new Dictionary<string, DataTypeReference>(), new Dictionary<string, INullable>(), null), CommandBehavior.Default);
             var dataTable = new DataTable();
             dataTable.Load(dataReader);
 
@@ -1507,7 +1509,7 @@ public void AggregateExpressionsWithoutGrouping()
         {
             var query = "SELECT count(DISTINCT firstname + ' ' + lastname) AS distinctnames FROM contact";
 
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
             var queries = planBuilder.Build(query, null, out _);
 
             AssertFetchXml(queries, @"
@@ -1545,7 +1547,7 @@ public void AggregateExpressionsWithoutGrouping()
                 }
             };
 
-            var dataReader = ((SelectNode)queries[0]).Execute(new NodeExecutionContext(GetDataSources(_context), this, new Dictionary<string, DataTypeReference>(), new Dictionary<string, INullable>(), null), CommandBehavior.Default);
+            var dataReader = ((SelectNode)queries[0]).Execute(new NodeExecutionContext(new SessionContext(GetDataSources(_context), this), this, new Dictionary<string, DataTypeReference>(), new Dictionary<string, INullable>(), null), CommandBehavior.Default);
             var dataTable = new DataTable();
             dataTable.Load(dataReader);
 
@@ -1559,7 +1561,7 @@ public void AggregateQueryProducesAlternative()
         {
             var query = "SELECT name, count(*) FROM account GROUP BY name ORDER BY 2 DESC";
 
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
             var queries = planBuilder.Build(query, null, out _);
 
             var select = (SelectNode)queries[0];
@@ -1600,7 +1602,7 @@ public void AggregateQueryProducesAlternative()
                 }
             };
 
-            var dataReader = alternativeQuery.Execute(new NodeExecutionContext(GetDataSources(_context), this, new Dictionary<string, DataTypeReference>(), new Dictionary<string, INullable>(), null), CommandBehavior.Default);
+            var dataReader = alternativeQuery.Execute(new NodeExecutionContext(new SessionContext(GetDataSources(_context), this), this, new Dictionary<string, DataTypeReference>(), new Dictionary<string, INullable>(), null), CommandBehavior.Default);
             var dataTable = new DataTable();
             dataTable.Load(dataReader);
 
@@ -1617,7 +1619,7 @@ public void GuidEntityReferenceInequality()
             {
                 var query = "SELECT a.name FROM account a INNER JOIN contact c ON a.primarycontactid = c.contactid WHERE (c.parentcustomerid is null or a.accountid <> c.parentcustomerid)";
 
-                var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+                var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
                 var queries = planBuilder.Build(query, null, out _);
 
                 var select = (SelectNode)queries[0];
@@ -1656,7 +1658,7 @@ public void GuidEntityReferenceInequality()
                     }
                 };
 
-                var dataReader = select.Execute(new NodeExecutionContext(GetDataSources(_context), this, new Dictionary<string, DataTypeReference>(), new Dictionary<string, INullable>(), null), CommandBehavior.Default);
+                var dataReader = select.Execute(new NodeExecutionContext(new SessionContext(GetDataSources(_context), this), this, new Dictionary<string, DataTypeReference>(), new Dictionary<string, INullable>(), null), CommandBehavior.Default);
                 var dataTable = new DataTable();
                 dataTable.Load(dataReader);
 
@@ -1671,7 +1673,7 @@ public void UpdateGuidToEntityReference()
         {
             var query = "UPDATE a SET primarycontactid = c.contactid FROM account AS a INNER JOIN contact AS c ON a.accountid = c.parentcustomerid";
 
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
             var queries = planBuilder.Build(query, null, out _);
 
             var update = (UpdateNode)queries[0];
@@ -1708,7 +1710,7 @@ public void UpdateGuidToEntityReference()
                 }
             };
 
-            update.Execute(new NodeExecutionContext(GetDataSources(_context), this, new Dictionary<string, DataTypeReference>(), new Dictionary<string, INullable>(), null), out _, out _);
+            update.Execute(new NodeExecutionContext(new SessionContext(GetDataSources(_context), this), this, new Dictionary<string, DataTypeReference>(), new Dictionary<string, INullable>(), null), out _, out _);
 
             Assert.AreEqual(new EntityReference("contact", contact1), _context.Data["account"][account1].GetAttributeValue<EntityReference>("primarycontactid"));
             Assert.AreEqual(new EntityReference("contact", contact2), _context.Data["account"][account2].GetAttributeValue<EntityReference>("primarycontactid"));
@@ -1719,7 +1721,7 @@ public void CompareDateFields()
         {
             var query = "DELETE c2 FROM contact c1 INNER JOIN contact c2 ON c1.parentcustomerid = c2.parentcustomerid AND c2.createdon > c1.createdon";
 
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
             var queries = planBuilder.Build(query, null, out _);
 
             AssertFetchXml(queries, @"
@@ -1744,7 +1746,7 @@ public void ColumnComparison()
         {
             var query = "SELECT firstname, lastname FROM contact WHERE firstname = lastname";
 
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
             var queries = planBuilder.Build(query, null, out _);
 
             AssertFetchXml(queries, @"
@@ -1767,7 +1769,7 @@ public void QuotedIdentifierError()
 
             try
             {
-                var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, new OptionsWrapper(this) { QuotedIdentifiers = true });
+                var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, new OptionsWrapper(this) { QuotedIdentifiers = true }), new OptionsWrapper(this) { QuotedIdentifiers = true });
                 var queries = planBuilder.Build(query, null, out _);
 
                 Assert.Fail("Expected exception");
@@ -1783,7 +1785,7 @@ public void FilterExpressionConstantValueToFetchXml()
         {
             var query = "SELECT firstname, lastname FROM contact WHERE firstname = 'Ma' + 'rk'";
 
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
             var queries = planBuilder.Build(query, null, out _);
 
             AssertFetchXml(queries, $@"
@@ -1804,7 +1806,7 @@ public void Count1ConvertedToCountStar()
         {
             var query = "SELECT COUNT(1) FROM contact OPTION(USE HINT('RETRIEVE_TOTAL_RECORD_COUNT'))";
 
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
             var queries = planBuilder.Build(query, null, out _);
 
             var selectNode = (SelectNode)queries[0];
@@ -1817,7 +1819,7 @@ public void CaseInsensitive()
         {
             var query = "Select Name From Account";
 
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
             var queries = planBuilder.Build(query, null, out _);
 
             AssertFetchXml(queries, $@"
@@ -1834,7 +1836,7 @@ public void ContainsValues1()
         {
             var query = "SELECT new_name FROM new_customentity WHERE CONTAINS(new_optionsetvaluecollection, '1')";
 
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
             var queries = planBuilder.Build(query, null, out _);
 
             AssertFetchXml(queries, $@"
@@ -1856,7 +1858,7 @@ public void ContainsValuesFunction1()
         {
             var query = "SELECT new_name FROM new_customentity WHERE new_optionsetvaluecollection = containvalues(1)";
 
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
             var queries = planBuilder.Build(query, null, out _);
 
             AssertFetchXml(queries, $@"
@@ -1878,7 +1880,7 @@ public void ContainsValues()
         {
             var query = "SELECT new_name FROM new_customentity WHERE CONTAINS(new_optionsetvaluecollection, '1 OR 2')";
 
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
             var queries = planBuilder.Build(query, null, out _);
 
             AssertFetchXml(queries, $@"
@@ -1901,7 +1903,7 @@ public void ContainsValuesFunction()
         {
             var query = "SELECT new_name FROM new_customentity WHERE new_optionsetvaluecollection = containvalues(1, 2)";
 
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
             var queries = planBuilder.Build(query, null, out _);
 
             AssertFetchXml(queries, $@"
@@ -1924,7 +1926,7 @@ public void NotContainsValues()
         {
             var query = "SELECT new_name FROM new_customentity WHERE NOT CONTAINS(new_optionsetvaluecollection, '1 OR 2')";
 
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
             var queries = planBuilder.Build(query, null, out _);
 
             AssertFetchXml(queries, $@"
@@ -1961,7 +1963,7 @@ public void ImplicitTypeConversion()
         {
             var query = "SELECT employees / 2.0 AS half FROM account";
 
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
             var queries = planBuilder.Build(query, null, out _);
 
             var account1 = Guid.NewGuid();
@@ -1981,7 +1983,7 @@ public void ImplicitTypeConversion()
                 }
             };
 
-            var dataReader = ((SelectNode)queries[0]).Execute(new NodeExecutionContext(GetDataSources(_context), this, new Dictionary<string, DataTypeReference>(), new Dictionary<string, INullable>(), null), CommandBehavior.Default);
+            var dataReader = ((SelectNode)queries[0]).Execute(new NodeExecutionContext(new SessionContext(GetDataSources(_context), this), this, new Dictionary<string, DataTypeReference>(), new Dictionary<string, INullable>(), null), CommandBehavior.Default);
             var dataTable = new DataTable();
             dataTable.Load(dataReader);
 
@@ -1994,7 +1996,7 @@ public void ImplicitTypeConversionComparison()
         {
             var query = "SELECT accountid FROM account WHERE turnover / 2 > 10";
 
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
             var queries = planBuilder.Build(query, null, out _);
 
             var account1 = Guid.NewGuid();
@@ -2014,7 +2016,7 @@ public void ImplicitTypeConversionComparison()
                 }
             };
 
-            var dataReader = ((SelectNode)queries[0]).Execute(new NodeExecutionContext(GetDataSources(_context), this, new Dictionary<string, DataTypeReference>(), new Dictionary<string, INullable>(), null), CommandBehavior.Default);
+            var dataReader = ((SelectNode)queries[0]).Execute(new NodeExecutionContext(new SessionContext(GetDataSources(_context), this), this, new Dictionary<string, DataTypeReference>(), new Dictionary<string, INullable>(), null), CommandBehavior.Default);
             var dataTable = new DataTable();
             dataTable.Load(dataReader);
 
@@ -2026,7 +2028,7 @@ public void GlobalOptionSet()
         {
             var query = "SELECT displayname FROM metadata.globaloptionset WHERE name = 'test'";
 
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
             var queries = planBuilder.Build(query, null, out _);
 
             Assert.IsInstanceOfType(queries.Single(), typeof(SelectNode));
@@ -2038,7 +2040,7 @@ public void GlobalOptionSet()
             Assert.AreEqual("globaloptionset.name = 'test'", filterNode.Filter.ToNormalizedSql());
             var optionsetNode = (GlobalOptionSetQueryNode)filterNode.Source;
 
-            var dataReader = selectNode.Execute(new NodeExecutionContext(GetDataSources(_context), this, new Dictionary<string, DataTypeReference>(), new Dictionary<string, INullable>(), null), CommandBehavior.Default);
+            var dataReader = selectNode.Execute(new NodeExecutionContext(new SessionContext(GetDataSources(_context), this), this, new Dictionary<string, DataTypeReference>(), new Dictionary<string, INullable>(), null), CommandBehavior.Default);
             var dataTable = new DataTable();
             dataTable.Load(dataReader);
 
@@ -2050,7 +2052,7 @@ public void EntityDetails()
         {
             var query = "SELECT logicalname FROM metadata.entity ORDER BY 1";
 
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
             var queries = planBuilder.Build(query, null, out _);
 
             Assert.IsInstanceOfType(queries.Single(), typeof(SelectNode));
@@ -2059,7 +2061,7 @@ public void EntityDetails()
             var sortNode = (SortNode)selectNode.Source;
             var metadataNode = (MetadataQueryNode)sortNode.Source;
 
-            var dataReader = selectNode.Execute(new NodeExecutionContext(GetDataSources(_context), this, new Dictionary<string, DataTypeReference>(), new Dictionary<string, INullable>(), null), CommandBehavior.Default);
+            var dataReader = selectNode.Execute(new NodeExecutionContext(new SessionContext(GetDataSources(_context), this), this, new Dictionary<string, DataTypeReference>(), new Dictionary<string, INullable>(), null), CommandBehavior.Default);
             var dataTable = new DataTable();
             dataTable.Load(dataReader);
 
@@ -2074,10 +2076,10 @@ public void AttributeDetails()
         {
             var query = "SELECT e.logicalname, a.logicalname FROM metadata.entity e INNER JOIN metadata.attribute a ON e.logicalname = a.entitylogicalname WHERE e.logicalname = 'new_customentity' ORDER BY 1, 2";
 
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
             var queries = planBuilder.Build(query, null, out _);
 
-            var dataReader = ((SelectNode)queries[0]).Execute(new NodeExecutionContext(GetDataSources(_context), this, new Dictionary<string, DataTypeReference>(), new Dictionary<string, INullable>(), null), CommandBehavior.Default);
+            var dataReader = ((SelectNode)queries[0]).Execute(new NodeExecutionContext(new SessionContext(GetDataSources(_context), this), this, new Dictionary<string, DataTypeReference>(), new Dictionary<string, INullable>(), null), CommandBehavior.Default);
             var dataTable = new DataTable();
             dataTable.Load(dataReader);
 
@@ -2099,7 +2101,7 @@ public void OptionSetNameSelect()
         {
             var query = "SELECT new_optionsetvalue, new_optionsetvaluename FROM new_customentity ORDER BY new_optionsetvaluename";
 
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
             var queries = planBuilder.Build(query, null, out _);
 
             var record1 = Guid.NewGuid();
@@ -2135,7 +2137,7 @@ public void OptionSetNameSelect()
 
             CollectionAssert.AreEqual(new[] { "new_optionsetvalue", "new_optionsetvaluename" }, select.ColumnSet.Select(c => c.OutputColumn).ToList());
 
-            var dataReader = select.Execute(new NodeExecutionContext(GetDataSources(_context), this, new Dictionary<string, DataTypeReference>(), new Dictionary<string, INullable>(), null), CommandBehavior.Default);
+            var dataReader = select.Execute(new NodeExecutionContext(new SessionContext(GetDataSources(_context), this), this, new Dictionary<string, DataTypeReference>(), new Dictionary<string, INullable>(), null), CommandBehavior.Default);
             var dataTable = new DataTable();
             dataTable.Load(dataReader);
 
@@ -2150,7 +2152,7 @@ public void OptionSetNameFilter()
         {
             var query = "SELECT new_customentityid FROM new_customentity WHERE new_optionsetvaluename = 'Value1'";
 
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
             var queries = planBuilder.Build(query, null, out _);
 
             AssertFetchXml(queries, @"
@@ -2169,7 +2171,7 @@ public void EntityReferenceNameSelect()
         {
             var query = "SELECT primarycontactid, primarycontactidname FROM account ORDER BY primarycontactidname";
 
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
             var queries = planBuilder.Build(query, null, out _);
 
             AssertFetchXml(queries, @"
@@ -2190,7 +2192,7 @@ public void EntityReferenceNameFilter()
         {
             var query = "SELECT accountid FROM account WHERE primarycontactidname = 'Mark Carrington'";
 
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
             var queries = planBuilder.Build(query, null, out _);
 
             AssertFetchXml(queries, @"
@@ -2209,7 +2211,7 @@ public void UpdateMissingAlias()
         {
             var query = "UPDATE account SET primarycontactid = c.contactid FROM account AS a INNER JOIN contact AS c ON a.name = c.fullname";
 
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
             var queries = planBuilder.Build(query, null, out _);
         }
 
@@ -2220,7 +2222,7 @@ public void UpdateMissingAliasAmbiguous()
 
             try
             {
-                var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+                var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
                 var queries = planBuilder.Build(query, null, out _);
                 Assert.Fail("Expected exception");
             }
@@ -2235,7 +2237,7 @@ public void ConvertIntToBool()
         {
             var query = "UPDATE new_customentity SET new_boolprop = CASE WHEN new_name = 'True' THEN 1 ELSE 0 END";
 
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
             var queries = planBuilder.Build(query, null, out _);
         }
 
@@ -2246,7 +2248,7 @@ public void ImpersonateRevert()
                 EXECUTE AS LOGIN = 'test1'
                 REVERT";
 
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
             var queries = planBuilder.Build(query, null, out _);
 
             Assert.IsInstanceOfType(queries[0], typeof(ExecuteAsNode));
@@ -2271,7 +2273,7 @@ SELECT contact.fullname
                 FROM contact INNER JOIN account ON contact.contactid = account.primarycontactid INNER JOIN new_customentity ON contact.parentcustomerid = new_customentity.new_parentid
                 ORDER BY account.employees, contact.fullname";
 
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
             var queries = planBuilder.Build(query, null, out _);
 
             AssertFetchXml(new[] { queries[0] }, @"
@@ -2361,7 +2363,7 @@ private void BuildTDSQuery(Action<ExecutionPlanBuilder> action)
             ds.Connection = null;
             try
             {
-                var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, new OptionsWrapper(this) { UseTDSEndpoint = true });
+                var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, new OptionsWrapper(this) { UseTDSEndpoint = true }), new OptionsWrapper(this) { UseTDSEndpoint = true });
                 action(planBuilder);
             }
             finally
@@ -2375,7 +2377,7 @@ public void OrderByAggregateByIndex()
         {
             var query = "SELECT firstname, count(*) FROM contact GROUP BY firstname ORDER BY 2";
 
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
             var queries = planBuilder.Build(query, null, out _);
 
             AssertFetchXml(queries, @"
@@ -2394,7 +2396,7 @@ public void OrderByAggregateJoinByIndex()
         {
             var query = "SELECT firstname, count(*) FROM contact INNER JOIN account ON contact.parentcustomerid = account.accountid GROUP BY firstname ORDER BY 2";
 
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
             var queries = planBuilder.Build(query, null, out _);
 
             AssertFetchXml(queries, @"
@@ -2415,7 +2417,7 @@ public void AggregateAlternativeDoesNotOrderByLinkEntity()
         {
             var query = "SELECT name, count(*) FROM contact INNER JOIN account ON contact.parentcustomerid = account.accountid GROUP BY name";
 
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
             var queries = planBuilder.Build(query, null, out _);
 
             var select = (SelectNode)queries[0];
@@ -2445,7 +2447,7 @@ public void CharIndex()
         {
             var query = "SELECT CHARINDEX('a', fullname) AS ci0, CHARINDEX('a', fullname, 1) AS ci1, CHARINDEX('a', fullname, 2) AS ci2, CHARINDEX('a', fullname, 3) AS ci3, CHARINDEX('a', fullname, 8) AS ci8 FROM contact";
 
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
             var queries = planBuilder.Build(query, null, out _);
 
             var contact1 = Guid.NewGuid();
@@ -2459,7 +2461,7 @@ public void CharIndex()
                 }
             };
 
-            var dataReader = ((SelectNode)queries[0]).Execute(new NodeExecutionContext(GetDataSources(_context), this, new Dictionary<string, DataTypeReference>(), new Dictionary<string, INullable>(), null), CommandBehavior.Default);
+            var dataReader = ((SelectNode)queries[0]).Execute(new NodeExecutionContext(new SessionContext(GetDataSources(_context), this), this, new Dictionary<string, DataTypeReference>(), new Dictionary<string, INullable>(), null), CommandBehavior.Default);
             var dataTable = new DataTable();
             dataTable.Load(dataReader);
 
@@ -2475,7 +2477,7 @@ public void CastDateTimeToDate()
         {
             var query = "SELECT CAST(createdon AS date) AS converted FROM contact";
 
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
             var queries = planBuilder.Build(query, null, out _);
 
             var contact1 = Guid.NewGuid();
@@ -2489,7 +2491,7 @@ public void CastDateTimeToDate()
                 }
             };
 
-            var dataReader = ((SelectNode)queries[0]).Execute(new NodeExecutionContext(GetDataSources(_context), this, new Dictionary<string, DataTypeReference>(), new Dictionary<string, INullable>(), null), CommandBehavior.Default);
+            var dataReader = ((SelectNode)queries[0]).Execute(new NodeExecutionContext(new SessionContext(GetDataSources(_context), this), this, new Dictionary<string, DataTypeReference>(), new Dictionary<string, INullable>(), null), CommandBehavior.Default);
             var dataTable = new DataTable();
             dataTable.Load(dataReader);
 
@@ -2501,7 +2503,7 @@ public void GroupByPrimaryFunction()
         {
             var query = "SELECT left(firstname, 1) AS initial, count(*) AS count FROM contact GROUP BY left(firstname, 1) ORDER BY 2 DESC";
 
-            var planBuilder = new ExecutionPlanBuilder(_localDataSources.Values, this);
+            var planBuilder = new ExecutionPlanBuilder(new SessionContext(_localDataSources, this), this);
             var queries = planBuilder.Build(query, null, out _);
 
             var contact1 = Guid.NewGuid();
@@ -2527,7 +2529,7 @@ public void GroupByPrimaryFunction()
                 }
             };
 
-            var dataReader = ((SelectNode)queries[0]).Execute(new NodeExecutionContext(GetDataSources(_context), this, new Dictionary<string, DataTypeReference>(), new Dictionary<string, INullable>(), null), CommandBehavior.Default);
+            var dataReader = ((SelectNode)queries[0]).Execute(new NodeExecutionContext(new SessionContext(GetDataSources(_context), this), this, new Dictionary<string, DataTypeReference>(), new Dictionary<string, INullable>(), null), CommandBehavior.Default);
             var dataTable = new DataTable();
             dataTable.Load(dataReader);
 
diff --git a/MarkMpn.Sql4Cds.Engine.Tests/SqlDateTests.cs b/MarkMpn.Sql4Cds.Engine.Tests/SqlDateTests.cs
new file mode 100644
index 00000000..d459d885
--- /dev/null
+++ b/MarkMpn.Sql4Cds.Engine.Tests/SqlDateTests.cs
@@ -0,0 +1,127 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+
+namespace MarkMpn.Sql4Cds.Engine.Tests
+{
+    [TestClass]
+    public class SqlDateTests
+    {
+        [DataTestMethod]
+        [DataRow("[M]M/dd/[yy]yy", "M/d/yy;M/d/yyyy;M/dd/yy;M/dd/yyyy;MM/d/yy;MM/d/yyyy;MM/dd/yy;MM/dd/yyyy")]
+        public void ConvertSqlFormatStringToNet(string input, string expected)
+        {
+            var actual = SqlDateParsing.SqlToNetFormatString(input);
+            CollectionAssert.AreEquivalent(expected.Split(';'), actual);
+        }
+
+        [DataTestMethod]
+        [DataRow("4/21/2007")]
+        [DataRow("4-21-2007")]
+        [DataRow("4.21.2007")]
+        [DataRow("Apr 21, 2007")]
+        [DataRow("Apr 2007 21")]
+        [DataRow("21 April, 2007")]
+        [DataRow("21 2007 Apr")]
+        [DataRow("2007 April 21")]
+        [DataRow("2007-04-21")]
+        [DataRow("20070421")]
+        public void ParseMDY(string input)
+        {
+            Assert.IsTrue(SqlDate.TryParse(input, DateFormat.mdy, out var actual));
+            Assert.AreEqual(new DateTime(2007, 4, 21), actual.Value);
+        }
+
+        [DataTestMethod]
+        [DataRow("4/2007/21")]
+        [DataRow("4-2007-21")]
+        [DataRow("4.2007.21")]
+        [DataRow("Apr 21, 2007")]
+        [DataRow("Apr 2007 21")]
+        [DataRow("21 April, 2007")]
+        [DataRow("21 2007 Apr")]
+        [DataRow("2007 April 21")]
+        [DataRow("2007-04-21")]
+        [DataRow("20070421")]
+        public void ParseMYD(string input)
+        {
+            Assert.IsTrue(SqlDate.TryParse(input, DateFormat.myd, out var actual));
+            Assert.AreEqual(new DateTime(2007, 4, 21), actual.Value);
+        }
+
+        [DataTestMethod]
+        [DataRow("21/4/2007")]
+        [DataRow("21-4-2007")]
+        [DataRow("21.4.2007")]
+        [DataRow("Apr 21, 2007")]
+        [DataRow("Apr 2007 21")]
+        [DataRow("21 April, 2007")]
+        [DataRow("21 2007 Apr")]
+        [DataRow("2007 April 21")]
+        [DataRow("2007-04-21")]
+        [DataRow("20070421")]
+        public void ParseDMY(string input)
+        {
+            Assert.IsTrue(SqlDate.TryParse(input, DateFormat.dmy, out var actual));
+            Assert.AreEqual(new DateTime(2007, 4, 21), actual.Value);
+        }
+
+        [DataTestMethod]
+        [DataRow("21/2007/4")]
+        [DataRow("21-2007-4")]
+        [DataRow("21.2007.4")]
+        [DataRow("Apr 21, 2007")]
+        [DataRow("Apr 2007 21")]
+        [DataRow("21 April, 2007")]
+        [DataRow("21 2007 Apr")]
+        [DataRow("2007 April 21")]
+        [DataRow("2007-04-21")]
+        [DataRow("20070421")]
+        public void ParseDYM(string input)
+        {
+            Assert.IsTrue(SqlDate.TryParse(input, DateFormat.dym, out var actual));
+            Assert.AreEqual(new DateTime(2007, 4, 21), actual.Value);
+        }
+
+        [DataTestMethod]
+        [DataRow("2007/4/21")]
+        [DataRow("2007-4-21")]
+        [DataRow("2007.4.21")]
+        [DataRow("Apr 21, 2007")]
+        [DataRow("Apr 2007 21")]
+        [DataRow("21 April, 2007")]
+        [DataRow("21 2007 Apr")]
+        [DataRow("2007 April 21")]
+        [DataRow("2007-04-21")]
+        [DataRow("20070421")]
+        public void ParseYMD(string input)
+        {
+            Assert.IsTrue(SqlDate.TryParse(input, DateFormat.ymd, out var actual));
+            Assert.AreEqual(new DateTime(2007, 4, 21), actual.Value);
+        }
+
+        [DataTestMethod]
+        [DataRow("12:30:45")] // TIME only
+        //[DataRow("+02:00")] // TIMEZONE only - mentioned as valid in documentation but doesn't work in practise
+        [DataRow("12:30:45+02:00")] // TIME + TIMEZONE
+        public void UseDefaultValuesForTimeStrings(string input)
+        {
+            // https://learn.microsoft.com/en-us/sql/t-sql/data-types/date-transact-sql?view=sql-server-ver16#convert-string-literals-to-date
+            Assert.IsTrue(SqlDate.TryParse(input, DateFormat.ymd, out var actual));
+            Assert.AreEqual(new DateTime(1900, 1, 1), actual.Value);
+        }
+
+        [DataTestMethod]
+        [DataRow("2007-04-21 12:30:45")] // DATE + TIME
+        [DataRow("2007-04-21 12:30:45+02:00")] // DATE + TIME + TIMEZONE
+        public void IgnoreTime(string input)
+        {
+            // https://learn.microsoft.com/en-us/sql/t-sql/data-types/date-transact-sql?view=sql-server-ver16#convert-string-literals-to-date
+            Assert.IsTrue(SqlDate.TryParse(input, DateFormat.ymd, out var actual));
+            Assert.AreEqual(new DateTime(2007, 4, 21), actual.Value);
+        }
+    }
+}
diff --git a/MarkMpn.Sql4Cds.Engine.Tests/SqlDateTimeTests.cs b/MarkMpn.Sql4Cds.Engine.Tests/SqlDateTimeTests.cs
new file mode 100644
index 00000000..dd132651
--- /dev/null
+++ b/MarkMpn.Sql4Cds.Engine.Tests/SqlDateTimeTests.cs
@@ -0,0 +1,129 @@
+using System;
+using System.Collections.Generic;
+using System.Data.SqlTypes;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+
+namespace MarkMpn.Sql4Cds.Engine.Tests
+{
+    [TestClass]
+    public class SqlDateTimeTests
+    {
+        [DataTestMethod]
+        [DataRow("4/15/96", "mdy")]
+        [DataRow("04/15/96", "mdy")]
+        [DataRow("4/15/1996", "mdy")]
+        [DataRow("04/15/1996", "mdy")]
+
+        [DataRow("4-15-96", "mdy")]
+        [DataRow("04-15-96", "mdy")]
+        [DataRow("4-15-1996", "mdy")]
+        [DataRow("04-15-1996", "mdy")]
+
+        [DataRow("4.15.96", "mdy")]
+        [DataRow("04.15.96", "mdy")]
+        [DataRow("4.15.1996", "mdy")]
+        [DataRow("04.15.1996", "mdy")]
+
+        [DataRow("4/96/15", "myd")]
+        [DataRow("04/96/15", "myd")]
+        [DataRow("4/1996/15", "myd")]
+        [DataRow("04/1996/15", "myd")]
+
+        [DataRow("15/4/96", "dmy")]
+        [DataRow("15/04/96", "dmy")]
+        [DataRow("15/4/1996", "dmy")]
+        [DataRow("15/04/1996", "dmy")]
+
+        [DataRow("15/96/4", "dym")]
+        [DataRow("15/96/04", "dym")]
+        [DataRow("15/1996/4", "dym")]
+        [DataRow("15/1996/04", "dym")]
+
+        [DataRow("96/15/4", "ydm")]
+        [DataRow("96/15/04", "ydm")]
+        [DataRow("1996/15/4", "ydm")]
+        [DataRow("1996/15/04", "ydm")]
+
+        [DataRow("96/4/15", "ymd")]
+        [DataRow("96/04/15", "ymd")]
+        [DataRow("1996/4/15", "ymd")]
+        [DataRow("1996/04/15", "ymd")]
+        public void NumericDateFormat(string input, string order)
+        {
+            var format = (DateFormat)Enum.Parse(typeof(DateFormat), order);
+            Assert.IsTrue(SqlDateParsing.TryParse(input, format, out SqlDateTime actual));
+            Assert.AreEqual(new DateTime(1996, 4, 15), actual.Value);
+        }
+
+        [DataTestMethod]
+        [DataRow("04/15/1996 14:30", "14:30:00")]
+        [DataRow("04/15/1996 14:30:20", "14:30:20")]
+        [DataRow("04/15/1996 14:30:20:997", "14:30:20.997")]
+        [DataRow("04/15/1996 14:30:20.9", "14:30:20.9")]
+        [DataRow("04/15/1996 4am", "04:00:00")]
+        [DataRow("04/15/1996 4 PM", "16:00:00")]
+        public void NumericDateFormatWithTime(string input, string expectedTime)
+        {
+            Assert.IsTrue(SqlDateParsing.TryParse(input, DateFormat.mdy, out SqlDateTime actual));
+            Assert.AreEqual(new DateTime(1996, 4, 15), actual.Value.Date);
+            Assert.AreEqual(TimeSpan.Parse(expectedTime), actual.Value.TimeOfDay);
+        }
+
+        [DataTestMethod]
+        [DataRow("Apr 1996", false)]
+        [DataRow("April 1996", false)]
+        [DataRow("April 15 1996", true)]
+        [DataRow("April 15, 1996", true)]
+        [DataRow("April 15 96", true)]
+        [DataRow("April 15, 96", true)]
+        [DataRow("Apr 1996 15", true)]
+        [DataRow("April 1996 15", true)]
+        [DataRow("Apr, 1996", false)]
+        [DataRow("April, 1996", false)]
+        [DataRow("15 Apr, 1996", true)]
+        [DataRow("15 April, 1996", true)]
+        [DataRow("15 Apr,1996", true)]
+        [DataRow("15 April,1996", true)]
+        [DataRow("15 Apr,96", true)]
+        [DataRow("15 April,96", true)]
+        [DataRow("15 Apr96", true)]
+        [DataRow("15 April96", true)]
+        [DataRow("15 96 apr", true)]
+        [DataRow("15 96 april", true)]
+        [DataRow("15 1996 apr", true)]
+        [DataRow("15 1996 april", true)]
+        [DataRow("1996 apr", false)]
+        [DataRow("1996 april", false)]
+        [DataRow("1996 apr 15", true)]
+        [DataRow("1996 april 15", true)]
+        [DataRow("1996 15 apr", true)]
+        [DataRow("1996 15 april", true)]
+        public void AlphaFormat(string input, bool includesDay)
+        {
+            Assert.IsTrue(SqlDateParsing.TryParse(input, DateFormat.mdy, out SqlDateTime actual));
+
+            if (includesDay)
+                Assert.AreEqual(new DateTime(1996, 4, 15), actual.Value);
+            else
+                Assert.AreEqual(new DateTime(1996, 4, 1), actual.Value);
+        }
+
+        [DataTestMethod]
+        [DataRow("2004-05-23T14:25:10", false)]
+        [DataRow("2004-05-23T14:25:10.487", true)]
+        [DataRow("20040523 14:25:10", false)]
+        [DataRow("20040523 14:25:10.487", true)]
+        public void IsoFormat(string input, bool milli)
+        {
+            Assert.IsTrue(SqlDateParsing.TryParse(input, DateFormat.mdy, out SqlDateTime actual));
+
+            if (milli)
+                Assert.AreEqual(new DateTime(2004, 5, 23, 14, 25, 10, 487), actual.Value);
+            else
+                Assert.AreEqual(new DateTime(2004, 5, 23, 14, 25, 10), actual.Value);
+        }
+    }
+}
diff --git a/MarkMpn.Sql4Cds.Engine.Tests/SqlTimeTests.cs b/MarkMpn.Sql4Cds.Engine.Tests/SqlTimeTests.cs
new file mode 100644
index 00000000..967b26a6
--- /dev/null
+++ b/MarkMpn.Sql4Cds.Engine.Tests/SqlTimeTests.cs
@@ -0,0 +1,15 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+
+namespace MarkMpn.Sql4Cds.Engine.Tests
+{
+    [TestClass]
+    public class SqlTimeTests
+    {
+        //public void ParseTime
+    }
+}
diff --git a/MarkMpn.Sql4Cds.Engine.Tests/SqlVariantTests.cs b/MarkMpn.Sql4Cds.Engine.Tests/SqlVariantTests.cs
index 5d610416..ff81d206 100644
--- a/MarkMpn.Sql4Cds.Engine.Tests/SqlVariantTests.cs
+++ b/MarkMpn.Sql4Cds.Engine.Tests/SqlVariantTests.cs
@@ -4,19 +4,33 @@
 using System.Linq;
 using System.Text;
 using System.Threading.Tasks;
+using Microsoft.SqlServer.TransactSql.ScriptDom;
 using Microsoft.VisualStudio.TestTools.UnitTesting;
 
 namespace MarkMpn.Sql4Cds.Engine.Tests
 {
     [TestClass]
-    public class SqlVariantTests
+    public class SqlVariantTests : FakeXrmEasyTestsBase
     {
+        private readonly ExpressionExecutionContext _eec;
+
+        public SqlVariantTests()
+        {
+            _eec = new ExpressionExecutionContext(
+                session: new SessionContext(_localDataSources, new StubOptions()),
+                options: new StubOptions(),
+                parameterTypes: new Dictionary<string, DataTypeReference>(),
+                parameterValues: new Dictionary<string, INullable>(),
+                log: e => { },
+                entity: null);
+        }
+
         [TestMethod]
         public void NullSortsBeforeAllOtherValues()
         {
             Assert.IsTrue(SqlVariant.Null.CompareTo(SqlVariant.Null) == 0);
-            Assert.IsTrue(SqlVariant.Null.CompareTo(new SqlVariant(DataTypeHelpers.Int, new SqlInt32(1))) < 0);
-            Assert.IsTrue(new SqlVariant(DataTypeHelpers.Int, new SqlInt32(1)).CompareTo(SqlVariant.Null) > 0);
+            Assert.IsTrue(SqlVariant.Null.CompareTo(new SqlVariant(DataTypeHelpers.Int, new SqlInt32(1), _eec)) < 0);
+            Assert.IsTrue(new SqlVariant(DataTypeHelpers.Int, new SqlInt32(1), _eec).CompareTo(SqlVariant.Null) > 0);
         }
 
         [TestMethod]
@@ -28,26 +42,26 @@ public void NullDoesNotEqualNull()
         [TestMethod]
         public void ValuesFromDifferentFamiliesAreNotEqual()
         {
-            Assert.AreEqual(new SqlVariant(DataTypeHelpers.VarChar(1, Collation.USEnglish, CollationLabel.CoercibleDefault), Collation.USEnglish.ToSqlString("1")) == new SqlVariant(DataTypeHelpers.Int, new SqlInt32(1)), (SqlBoolean)false);
+            Assert.AreEqual(new SqlVariant(DataTypeHelpers.VarChar(1, Collation.USEnglish, CollationLabel.CoercibleDefault), Collation.USEnglish.ToSqlString("1"), _eec) == new SqlVariant(DataTypeHelpers.Int, new SqlInt32(1), _eec), (SqlBoolean)false);
         }
 
         [TestMethod]
         public void ValuesFromDifferentTypesInSameFamilyAreEqual()
         {
-            Assert.AreEqual(new SqlVariant(DataTypeHelpers.BigInt, new SqlInt64(1)) == new SqlVariant(DataTypeHelpers.Int, new SqlInt32(1)), (SqlBoolean)true);
+            Assert.AreEqual(new SqlVariant(DataTypeHelpers.BigInt, new SqlInt64(1), _eec) == new SqlVariant(DataTypeHelpers.Int, new SqlInt32(1), _eec), (SqlBoolean)true);
         }
 
         [TestMethod]
         public void SortsAccordingToDataTypeFamilies()
         {
             var variant = SqlVariant.Null;
-            var dt = new SqlVariant(DataTypeHelpers.DateTime, new SqlDateTime(2000, 1, 1));
-            var approx = new SqlVariant(DataTypeHelpers.Float, new SqlSingle(1));
-            var exact = new SqlVariant(DataTypeHelpers.Int, new SqlInt32(1));
-            var ch = new SqlVariant(DataTypeHelpers.VarChar(10, Collation.USEnglish, CollationLabel.CoercibleDefault), Collation.USEnglish.ToSqlString("1"));
-            var nch = new SqlVariant(DataTypeHelpers.NVarChar(10, Collation.USEnglish, CollationLabel.CoercibleDefault), Collation.USEnglish.ToSqlString("1"));
-            var bin = new SqlVariant(DataTypeHelpers.VarBinary(10), new SqlBinary(new byte[] { 1 }));
-            var guid = new SqlVariant(DataTypeHelpers.UniqueIdentifier, new SqlGuid(Guid.NewGuid()));
+            var dt = new SqlVariant(DataTypeHelpers.DateTime, new SqlDateTime(2000, 1, 1), _eec);
+            var approx = new SqlVariant(DataTypeHelpers.Float, new SqlSingle(1), _eec);
+            var exact = new SqlVariant(DataTypeHelpers.Int, new SqlInt32(1), _eec);
+            var ch = new SqlVariant(DataTypeHelpers.VarChar(10, Collation.USEnglish, CollationLabel.CoercibleDefault), Collation.USEnglish.ToSqlString("1"), _eec);
+            var nch = new SqlVariant(DataTypeHelpers.NVarChar(10, Collation.USEnglish, CollationLabel.CoercibleDefault), Collation.USEnglish.ToSqlString("1"), _eec);
+            var bin = new SqlVariant(DataTypeHelpers.VarBinary(10), new SqlBinary(new byte[] { 1 }), _eec);
+            var guid = new SqlVariant(DataTypeHelpers.UniqueIdentifier, new SqlGuid(Guid.NewGuid()), _eec);
 
             var list = new List<SqlVariant> { variant, dt, approx, exact, ch, nch, bin, guid };
             var rnd = new Random();
diff --git a/MarkMpn.Sql4Cds.Engine.Tests/StubOptions.cs b/MarkMpn.Sql4Cds.Engine.Tests/StubOptions.cs
index fbb0655b..6871535d 100644
--- a/MarkMpn.Sql4Cds.Engine.Tests/StubOptions.cs
+++ b/MarkMpn.Sql4Cds.Engine.Tests/StubOptions.cs
@@ -31,6 +31,8 @@ class StubOptions : IQueryExecutionOptions
 
         ColumnOrdering IQueryExecutionOptions.ColumnOrdering => ColumnOrdering.Alphabetical;
 
+        public event EventHandler PrimaryDataSourceChanged;
+
         void IQueryExecutionOptions.ConfirmInsert(ConfirmDmlStatementEventArgs e)
         {
         }
diff --git a/MarkMpn.Sql4Cds.Engine/Ado/CancellationTokenOptionsWrapper.cs b/MarkMpn.Sql4Cds.Engine/Ado/CancellationTokenOptionsWrapper.cs
index 5598817b..02133e8e 100644
--- a/MarkMpn.Sql4Cds.Engine/Ado/CancellationTokenOptionsWrapper.cs
+++ b/MarkMpn.Sql4Cds.Engine/Ado/CancellationTokenOptionsWrapper.cs
@@ -45,6 +45,19 @@ public CancellationTokenOptionsWrapper(IQueryExecutionOptions options, Cancellat
 
         public ColumnOrdering ColumnOrdering => _options.ColumnOrdering;
 
+        public event EventHandler PrimaryDataSourceChanged
+        {
+            add
+            {
+                _options.PrimaryDataSourceChanged += value;
+            }
+
+            remove
+            {
+                _options.PrimaryDataSourceChanged -= value;
+            }
+        }
+
         public void ConfirmDelete(ConfirmDmlStatementEventArgs e)
         {
             _options.ConfirmDelete(e);
diff --git a/MarkMpn.Sql4Cds.Engine/Ado/ChangeDatabaseOptionsWrapper.cs b/MarkMpn.Sql4Cds.Engine/Ado/ChangeDatabaseOptionsWrapper.cs
deleted file mode 100644
index 0c89a9ec..00000000
--- a/MarkMpn.Sql4Cds.Engine/Ado/ChangeDatabaseOptionsWrapper.cs
+++ /dev/null
@@ -1,107 +0,0 @@
-using System;
-using System.Collections.Generic;
-using System.Text;
-using System.Threading;
-using Microsoft.Xrm.Sdk.Metadata;
-using Microsoft.Xrm.Sdk.Query;
-
-namespace MarkMpn.Sql4Cds.Engine
-{
-    class ChangeDatabaseOptionsWrapper : IQueryExecutionOptions
-    {
-        private readonly Sql4CdsConnection _connection;
-        private readonly IQueryExecutionOptions _options;
-        
-        public ChangeDatabaseOptionsWrapper(Sql4CdsConnection connection, IQueryExecutionOptions options)
-        {
-            _connection = connection;
-            _options = options;
-
-            PrimaryDataSource = options.PrimaryDataSource;
-            UseTDSEndpoint = options.UseTDSEndpoint;
-            BlockUpdateWithoutWhere = options.BlockUpdateWithoutWhere;
-            BlockDeleteWithoutWhere = options.BlockDeleteWithoutWhere;
-            UseBulkDelete = options.UseBulkDelete;
-            BatchSize = options.BatchSize;
-            MaxDegreeOfParallelism = options.MaxDegreeOfParallelism;
-            UseLocalTimeZone = options.UseLocalTimeZone;
-            BypassCustomPlugins = options.BypassCustomPlugins;
-            QuotedIdentifiers = options.QuotedIdentifiers;
-            ColumnOrdering = options.ColumnOrdering;
-        }
-
-        public CancellationToken CancellationToken => _options.CancellationToken;
-
-        public bool BlockUpdateWithoutWhere { get; set; }
-
-        public bool BlockDeleteWithoutWhere { get; set; }
-
-        public bool UseBulkDelete { get; set; }
-
-        public int BatchSize { get; set; }
-
-        public bool UseTDSEndpoint { get; set; }
-
-        public int MaxDegreeOfParallelism { get; set; }
-
-        public bool UseLocalTimeZone { get; set; }
-
-        public bool BypassCustomPlugins { get; set; }
-
-        public string PrimaryDataSource { get; set; } // TODO: Update UserId when changing data source
-
-        public Guid UserId => _options.UserId;
-
-        public bool QuotedIdentifiers { get; set; }
-
-        public ColumnOrdering ColumnOrdering { get; set; }
-
-        public void ConfirmDelete(ConfirmDmlStatementEventArgs e)
-        {
-            if (!e.Cancel)
-                _options.ConfirmDelete(e);
-
-            if (!e.Cancel)
-                _connection.OnPreDelete(e);
-        }
-
-        public void ConfirmInsert(ConfirmDmlStatementEventArgs e)
-        {
-            if (!e.Cancel)
-                _options.ConfirmInsert(e);
-
-            if (!e.Cancel)
-                _connection.OnPreInsert(e);
-        }
-
-        public void ConfirmUpdate(ConfirmDmlStatementEventArgs e)
-        {
-            if (!e.Cancel)
-                _options.ConfirmUpdate(e);
-
-            if (!e.Cancel)
-                _connection.OnPreUpdate(e);
-        }
-
-        public bool ContinueRetrieve(int count)
-        {
-            var cancelled = !_options.ContinueRetrieve(count);
-
-            if (!cancelled)
-            {
-                var args = new ConfirmRetrieveEventArgs(count);
-                _connection.OnPreRetrieve(args);
-
-                cancelled = args.Cancel;
-            }
-
-            return !cancelled;
-        }
-
-        public void Progress(double? progress, string message)
-        {
-            _options.Progress(progress, message);
-            _connection.OnProgress(new ProgressEventArgs(progress, message));
-        }
-    }
-}
diff --git a/MarkMpn.Sql4Cds.Engine/Ado/DefaultQueryExecutionOptions.cs b/MarkMpn.Sql4Cds.Engine/Ado/DefaultQueryExecutionOptions.cs
index 295d595f..9eb67536 100644
--- a/MarkMpn.Sql4Cds.Engine/Ado/DefaultQueryExecutionOptions.cs
+++ b/MarkMpn.Sql4Cds.Engine/Ado/DefaultQueryExecutionOptions.cs
@@ -16,85 +16,126 @@ namespace MarkMpn.Sql4Cds.Engine
 {
     class DefaultQueryExecutionOptions : IQueryExecutionOptions
     {
-        public DefaultQueryExecutionOptions(DataSource dataSource, CancellationToken cancellationToken)
+        private readonly Sql4CdsConnection _connection;
+        private string _primaryDataSource;
+        private Guid? _userId;
+
+        public DefaultQueryExecutionOptions(Sql4CdsConnection connection, DataSource dataSource, CancellationToken cancellationToken)
         {
-            PrimaryDataSource = dataSource.Name;
+            _connection = connection;
+            _primaryDataSource = dataSource.Name;
             CancellationToken = cancellationToken;
 
-#if NETCOREAPP
-            if (dataSource.Connection is ServiceClient svc)
-            {
-                UserId = svc.GetMyUserId();
-            }
-#else
-            if (dataSource.Connection is CrmServiceClient svc)
-            {
-                UserId = svc.GetMyCrmUserId();
-            }
-#endif
-            else
-            {
-                var whoami = (WhoAmIResponse)dataSource.Connection.Execute(new WhoAmIRequest());
-                UserId = whoami.UserId;
-            }
-
+            PrimaryDataSourceChanged += (_, __) => _userId = null;
         }
 
         public CancellationToken CancellationToken { get; }
 
-        public bool BlockUpdateWithoutWhere => false;
+        public bool BlockUpdateWithoutWhere { get; set; }
 
-        public bool BlockDeleteWithoutWhere => false;
+        public bool BlockDeleteWithoutWhere { get; set; }
 
-        public bool UseBulkDelete => false;
+        public bool UseBulkDelete { get; set; }
 
-        public int BatchSize => 100;
+        public int BatchSize { get; set; } = 100;
 
-        public bool UseTDSEndpoint => true;
+        public bool UseTDSEndpoint { get; set; } = true;
 
-        public int MaxDegreeOfParallelism => 10;
+        public int MaxDegreeOfParallelism { get; set; } = 10;
 
         public bool ColumnComparisonAvailable { get; }
 
         public bool OrderByEntityNameAvailable { get; }
 
-        public bool UseLocalTimeZone => false;
+        public bool UseLocalTimeZone { get; set; }
 
         public List<JoinOperator> JoinOperatorsAvailable { get; }
 
-        public bool BypassCustomPlugins => false;
+        public bool BypassCustomPlugins { get; set; }
 
-        public string PrimaryDataSource { get; }
+        public string PrimaryDataSource
+        {
+            get => _primaryDataSource;
+            set
+            {
+                if (_primaryDataSource != value)
+                {
+                    _primaryDataSource = value;
+                    OnPrimaryDataSourceChanged();
+                }
+            }
+        }
+
+        public Guid UserId
+        {
+            get
+            {
+                if (_userId == null)
+                {
+#if NETCOREAPP
+                    if (_connection.Session.DataSources[PrimaryDataSource].Connection is ServiceClient svc)
+                    {
+                        _userId = svc.GetMyUserId();
+                    }
+#else
+                    if (_connection.Session.DataSources[PrimaryDataSource].Connection is CrmServiceClient svc)
+                    {
+                        _userId = svc.GetMyCrmUserId();
+                    }
+#endif
+                    else
+                    {
+                        var whoami = (WhoAmIResponse)_connection.Session.DataSources[PrimaryDataSource].Connection.Execute(new WhoAmIRequest());
+                        _userId = whoami.UserId;
+                    }
+                }
+
+                return _userId.Value;
+            }
+        }
 
-        public Guid UserId { get; }
+        public bool QuotedIdentifiers { get; set; } = true;
 
-        public bool QuotedIdentifiers => true;
+        public ColumnOrdering ColumnOrdering { get; set; }
 
-        public ColumnOrdering ColumnOrdering => ColumnOrdering.Strict;
+        public event EventHandler PrimaryDataSourceChanged;
 
         public void ConfirmDelete(ConfirmDmlStatementEventArgs e)
         {
+            if (!e.Cancel)
+                _connection.OnPreDelete(e);
         }
 
         public void ConfirmInsert(ConfirmDmlStatementEventArgs e)
         {
+            if (!e.Cancel)
+                _connection.OnPreInsert(e);
         }
 
         public void ConfirmUpdate(ConfirmDmlStatementEventArgs e)
         {
+            if (!e.Cancel)
+                _connection.OnPreUpdate(e);
         }
 
         public bool ContinueRetrieve(int count)
         {
-            return true;
+            var args = new ConfirmRetrieveEventArgs(count);
+            _connection.OnPreRetrieve(args);
+
+            var cancelled = args.Cancel;
+
+            return !cancelled;
         }
 
         public void Progress(double? progress, string message)
         {
+            _connection.OnProgress(new ProgressEventArgs(progress, message));
         }
 
-        public void RetrievingNextPage()
+        protected virtual void OnPrimaryDataSourceChanged()
         {
+            PrimaryDataSourceChanged?.Invoke(this, EventArgs.Empty);
         }
     }
 }
diff --git a/MarkMpn.Sql4Cds.Engine/Ado/Sql4CdsCommand.cs b/MarkMpn.Sql4Cds.Engine/Ado/Sql4CdsCommand.cs
index 6987088f..0610529f 100644
--- a/MarkMpn.Sql4Cds.Engine/Ado/Sql4CdsCommand.cs
+++ b/MarkMpn.Sql4Cds.Engine/Ado/Sql4CdsCommand.cs
@@ -48,7 +48,7 @@ public Sql4CdsCommand(Sql4CdsConnection connection, string commandText)
             CommandTimeout = 30;
             DbParameterCollection = new Sql4CdsParameterCollection();
 
-            _planBuilder = new ExecutionPlanBuilder(_connection.DataSources.Values, _connection.Options);
+            _planBuilder = new ExecutionPlanBuilder(_connection.Session, _connection.Options);
             _planBuilder.Log = msg => _connection.OnInfoMessage(null, msg);
         }
 
@@ -123,7 +123,7 @@ protected override DbConnection DbConnection
                     throw new ArgumentOutOfRangeException(nameof(value), "Connection must be a Sql4CdsConnection");
 
                 _connection = con;
-                _planBuilder = new ExecutionPlanBuilder(_connection.DataSources.Values, _connection.Options);
+                _planBuilder = new ExecutionPlanBuilder(_connection.Session, _connection.Options);
                 _planBuilder.Log = msg => _connection.OnInfoMessage(null, msg);
                 Plan = null;
                 UseTDSEndpointDirectly = false;
@@ -261,10 +261,10 @@ protected override DbDataReader ExecuteDbDataReader(CommandBehavior behavior)
                 if (UseTDSEndpointDirectly)
                 {
 #if NETCOREAPP
-                    var svc = (ServiceClient)_connection.DataSources[_connection.Database].Connection;
+                    var svc = (ServiceClient)_connection.Session.DataSources[_connection.Database].Connection;
                     var con = new SqlConnection("server=" + svc.ConnectedOrgUriActual.Host);
 #else
-                    var svc = (CrmServiceClient)_connection.DataSources[_connection.Database].Connection;
+                    var svc = (CrmServiceClient)_connection.Session.DataSources[_connection.Database].Connection;
                     var con = new SqlConnection("server=" + svc.CrmConnectOrgUriActual.Host);
 #endif
                     con.AccessToken = svc.CurrentAccessToken;
@@ -272,11 +272,11 @@ protected override DbDataReader ExecuteDbDataReader(CommandBehavior behavior)
 
                     var cmd = con.CreateCommand();
                     cmd.CommandTimeout = (int)TimeSpan.FromMinutes(2).TotalSeconds;
-                    cmd.CommandText = SqlNode.ApplyCommandBehavior(CommandText, behavior, _connection.Options);
+                    cmd.CommandText = SqlNode.ApplyCommandBehavior(CommandText, behavior, new NodeExecutionContext(null, _connection.Options, null, null, null));
                     var node = new SqlNode { Sql = cmd.CommandText, DataSource = _connection.Database };
                     cmd.StatementCompleted += (_, e) =>
                     {
-                        _connection.GlobalVariableValues["@@ROWCOUNT"] = (SqlInt32)e.RecordCount;
+                        _connection.Session.GlobalVariableValues["@@ROWCOUNT"] = (SqlInt32)e.RecordCount;
                         OnStatementCompleted(node, e.RecordCount, $"({e.RecordCount} {(e.RecordCount == 1 ? "row" : "rows")} affected)");
                     };
 
diff --git a/MarkMpn.Sql4Cds.Engine/Ado/Sql4CdsConnection.cs b/MarkMpn.Sql4Cds.Engine/Ado/Sql4CdsConnection.cs
index 167f66ac..4f8f7f78 100644
--- a/MarkMpn.Sql4Cds.Engine/Ado/Sql4CdsConnection.cs
+++ b/MarkMpn.Sql4Cds.Engine/Ado/Sql4CdsConnection.cs
@@ -26,11 +26,9 @@ namespace MarkMpn.Sql4Cds.Engine
     /// </summary>
     public class Sql4CdsConnection : DbConnection
     {
-        private readonly IDictionary<string, DataSource> _dataSources;
-        private readonly ChangeDatabaseOptionsWrapper _options;
-        private readonly Dictionary<string, DataTypeReference> _globalVariableTypes;
-        private readonly Dictionary<string, INullable> _globalVariableValues;
+        private readonly DefaultQueryExecutionOptions _options;
         private readonly TelemetryClient _ai;
+        private readonly SessionContext _session;
 
         /// <summary>
         /// Creates a new <see cref="Sql4CdsConnection"/> using the specified XRM connection string
@@ -61,27 +59,8 @@ public Sql4CdsConnection(IDictionary<string, DataSource> dataSources)
             if (dataSources.Count == 0)
                 throw new ArgumentOutOfRangeException("At least one data source must be supplied");
 
-            var options = new DefaultQueryExecutionOptions(dataSources.First().Value, CancellationToken.None);
-
-            _dataSources = dataSources;
-            _options = new ChangeDatabaseOptionsWrapper(this, options);
-
-            _globalVariableTypes = new Dictionary<string, DataTypeReference>(StringComparer.OrdinalIgnoreCase)
-            {
-                ["@@IDENTITY"] = DataTypeHelpers.EntityReference,
-                ["@@ROWCOUNT"] = DataTypeHelpers.Int,
-                ["@@SERVERNAME"] = DataTypeHelpers.NVarChar(100, _dataSources[_options.PrimaryDataSource].DefaultCollation, CollationLabel.CoercibleDefault),
-                ["@@VERSION"] = DataTypeHelpers.NVarChar(Int32.MaxValue, _dataSources[_options.PrimaryDataSource].DefaultCollation, CollationLabel.CoercibleDefault),
-                ["@@ERROR"] = DataTypeHelpers.Int,
-            };
-            _globalVariableValues = new Dictionary<string, INullable>(StringComparer.OrdinalIgnoreCase)
-            {
-                ["@@IDENTITY"] = SqlEntityReference.Null,
-                ["@@ROWCOUNT"] = (SqlInt32)0,
-                ["@@SERVERNAME"] = GetServerName(_dataSources[_options.PrimaryDataSource]),
-                ["@@VERSION"] = GetVersion(_dataSources[_options.PrimaryDataSource]),
-                ["@@ERROR"] = (SqlInt32)0,
-            };
+            _options = new DefaultQueryExecutionOptions(this, dataSources.First().Value, CancellationToken.None);
+            _session = new SessionContext(dataSources, _options);
 
             _ai = new TelemetryClient(new Microsoft.ApplicationInsights.Extensibility.TelemetryConfiguration("79761278-a908-4575-afbf-2f4d82560da6"));
 
@@ -93,51 +72,6 @@ public Sql4CdsConnection(IDictionary<string, DataSource> dataSources)
                 ApplicationName = "SQL 4 CDS ADO.NET Provider";
         }
 
-        private SqlString GetVersion(DataSource dataSource)
-        {
-            string orgVersion = null;
-
-#if NETCOREAPP
-            if (dataSource.Connection is ServiceClient svc)
-                orgVersion = svc.ConnectedOrgVersion.ToString();
-#else
-            if (dataSource.Connection is CrmServiceClient svc)
-                orgVersion = svc.ConnectedOrgVersion.ToString();
-#endif
-
-            if (orgVersion == null)
-                orgVersion = ((RetrieveVersionResponse)dataSource.Execute(new RetrieveVersionRequest())).Version;
-
-            var assembly = typeof(Sql4CdsConnection).Assembly;
-            var assemblyVersion = assembly.GetName().Version;
-            var assemblyCopyright = assembly
-                .GetCustomAttributes(typeof(AssemblyCopyrightAttribute), false)
-                .OfType<AssemblyCopyrightAttribute>()
-                .FirstOrDefault()?
-                .Copyright;
-            var assemblyFilename = assembly.Location;
-            var assemblyDate = System.IO.File.GetLastWriteTime(assemblyFilename);
-
-            return $"Microsoft Dataverse - {orgVersion}\r\n\tSQL 4 CDS - {assemblyVersion}\r\n\t{assemblyDate:MMM dd yyyy HH:mm:ss}\r\n\t{assemblyCopyright}";
-        }
-
-        private SqlString GetServerName(DataSource dataSource)
-        {
-#if NETCOREAPP
-            var svc = dataSource.Connection as ServiceClient;
-
-            if (svc != null)
-                return svc.ConnectedOrgUriActual.Host;
-#else
-            var svc = dataSource.Connection as CrmServiceClient;
-
-            if (svc != null)
-                return svc.CrmConnectOrgUriActual.Host;
-#endif
-
-            return dataSource.Name;
-        }
-
         private static IOrganizationService Connect(string connectionString)
         {
 #if NETCOREAPP
@@ -185,7 +119,7 @@ internal void OnInfoMessage(IRootExecutionPlanNode node, Sql4CdsError message)
             }
         }
 
-        internal IDictionary<string, DataSource> DataSources => _dataSources;
+        internal SessionContext Session => _session;
 
         internal IQueryExecutionOptions Options => _options;
 
@@ -289,10 +223,6 @@ public ColumnOrdering ColumnOrdering
             set => _options.ColumnOrdering = value;
         }
 
-        internal Dictionary<string, DataTypeReference> GlobalVariableTypes => _globalVariableTypes;
-
-        internal Dictionary<string, INullable> GlobalVariableValues => _globalVariableValues;
-
         internal TelemetryClient TelemetryClient => _ai;
 
         /// <summary>
@@ -371,7 +301,7 @@ public override string DataSource
         {
             get
             {
-                var dataSource = _dataSources[Database];
+                var dataSource = Session.DataSources[Database];
 
 #if NETCOREAPP
                 if (dataSource.Connection is ServiceClient svc)
@@ -389,7 +319,7 @@ public override string ServerVersion
         {
             get
             {
-                var dataSource = _dataSources[Database];
+                var dataSource = Session.DataSources[Database];
 
 #if NETCOREAPP
                 if (dataSource.Connection is ServiceClient svc)
@@ -408,7 +338,7 @@ public override string ServerVersion
 
         public override void ChangeDatabase(string databaseName)
         {
-            if (!_dataSources.ContainsKey(databaseName))
+            if (!Session.DataSources.ContainsKey(databaseName))
                 throw new Sql4CdsException(new Sql4CdsError(11, 0, 0, null, databaseName, 0, "Database is not in the list of connected databases", null));
 
             _options.PrimaryDataSource = databaseName;
diff --git a/MarkMpn.Sql4Cds.Engine/Ado/Sql4CdsDataReader.cs b/MarkMpn.Sql4Cds.Engine/Ado/Sql4CdsDataReader.cs
index a88c27d0..b9cc364f 100644
--- a/MarkMpn.Sql4Cds.Engine/Ado/Sql4CdsDataReader.cs
+++ b/MarkMpn.Sql4Cds.Engine/Ado/Sql4CdsDataReader.cs
@@ -1,17 +1,12 @@
 using System;
 using System.Collections;
-using System.Collections.Concurrent;
 using System.Collections.Generic;
 using System.Data;
 using System.Data.Common;
 using System.Data.SqlTypes;
 using System.Linq;
-using System.Linq.Expressions;
-using System.Text;
-using System.Xml;
 using MarkMpn.Sql4Cds.Engine.ExecutionPlan;
 using Microsoft.SqlServer.TransactSql.ScriptDom;
-using Microsoft.Xrm.Sdk;
 
 namespace MarkMpn.Sql4Cds.Engine
 {
@@ -21,8 +16,9 @@ class Sql4CdsDataReader : DbDataReader
         private readonly Sql4CdsCommand _command;
         private readonly IQueryExecutionOptions _options;
         private readonly CommandBehavior _behavior;
-        private readonly Dictionary<string, DataTypeReference> _parameterTypes;
-        private readonly Dictionary<string, INullable> _parameterValues;
+        private readonly LayeredDictionary<string, DataTypeReference> _parameterTypes;
+        private readonly LayeredDictionary<string, INullable> _parameterValues;
+        private readonly Stack<Sql4CdsError> _errorDetails;
         private Dictionary<string, int> _labelIndexes;
         private int _recordsAffected;
         private int _instructionPointer;
@@ -32,7 +28,6 @@ class Sql4CdsDataReader : DbDataReader
         private int _rows;
         private int _resultSetsReturned;
         private bool _closed;
-        private Stack<Sql4CdsError> _errorDetails;
         
         public Sql4CdsDataReader(Sql4CdsCommand command, IQueryExecutionOptions options, CommandBehavior behavior)
         {
@@ -42,14 +37,15 @@ public Sql4CdsDataReader(Sql4CdsCommand command, IQueryExecutionOptions options,
             _behavior = behavior;
             _recordsAffected = -1;
 
-            _parameterTypes = ((Sql4CdsParameterCollection)command.Parameters).GetParameterTypes();
-            _parameterValues = ((Sql4CdsParameterCollection)command.Parameters).GetParameterValues();
+            _parameterTypes = new LayeredDictionary<string, DataTypeReference>(
+                _connection.Session.GlobalVariableTypes,
+                ((Sql4CdsParameterCollection)command.Parameters).GetParameterTypes(),
+                new Dictionary<string, DataTypeReference>(StringComparer.OrdinalIgnoreCase));
 
-            foreach (var paramType in _connection.GlobalVariableTypes)
-                _parameterTypes[paramType.Key] = paramType.Value;
-
-            foreach (var paramValue in _connection.GlobalVariableValues)
-                _parameterValues[paramValue.Key] = paramValue.Value;
+            _parameterValues = new LayeredDictionary<string, INullable>(
+                _connection.Session.GlobalVariableValues,
+                ((Sql4CdsParameterCollection)command.Parameters).GetParameterValues(),
+                new Dictionary<string, INullable>(StringComparer.OrdinalIgnoreCase));
 
             _errorDetails = new Stack<Sql4CdsError>();
 
@@ -57,7 +53,7 @@ public Sql4CdsDataReader(Sql4CdsCommand command, IQueryExecutionOptions options,
                 Close();
         }
 
-        internal Dictionary<string, INullable> ParameterValues => _parameterValues;
+        internal IDictionary<string, INullable> ParameterValues => _parameterValues;
 
         private Dictionary<string, int> LabelIndexes
         {
@@ -75,7 +71,7 @@ private Dictionary<string, int> LabelIndexes
             }
         }
 
-        private bool ExecuteWithExceptionHandling(Dictionary<string, DataTypeReference> parameterTypes, Dictionary<string, INullable> parameterValues)
+        private bool ExecuteWithExceptionHandling(LayeredDictionary<string, DataTypeReference> parameterTypes, LayeredDictionary<string, INullable> parameterValues)
         {
             while (true)
             {
@@ -109,10 +105,10 @@ private bool ExecuteWithExceptionHandling(Dictionary<string, DataTypeReference>
             }
         }
 
-        private bool Execute(Dictionary<string, DataTypeReference> parameterTypes, Dictionary<string, INullable> parameterValues)
+        private bool Execute(LayeredDictionary<string, DataTypeReference> parameterTypes, LayeredDictionary<string, INullable> parameterValues)
         {
             IRootExecutionPlanNode logNode = null;
-            var context = new NodeExecutionContext(_connection.DataSources, _options, parameterTypes, parameterValues, msg => _connection.OnInfoMessage(logNode, msg));
+            var context = new NodeExecutionContext(_connection.Session, _options, parameterTypes, parameterValues, msg => _connection.OnInfoMessage(logNode, msg));
             context.Error = _errorDetails.FirstOrDefault();
 
             try
@@ -297,11 +293,6 @@ private bool Execute(Dictionary<string, DataTypeReference> parameterTypes, Dicti
                     throw sqlErr;
                 }
             }
-            finally
-            {
-                foreach (var paramName in _connection.GlobalVariableValues.Keys.ToArray())
-                    _connection.GlobalVariableValues[paramName] = parameterValues[paramName];
-            }
 
             if (_options.CancellationToken.IsCancellationRequested)
                 throw new Sql4CdsException(new Sql4CdsError(11, 0, 0, null, null, 0, _command.CancelledManually ? "Query was cancelled by user" : "Query timed out", null));
diff --git a/MarkMpn.Sql4Cds.Engine/Ado/Sql4CdsError.cs b/MarkMpn.Sql4Cds.Engine/Ado/Sql4CdsError.cs
index d6885f7c..9a6ed10c 100644
--- a/MarkMpn.Sql4Cds.Engine/Ado/Sql4CdsError.cs
+++ b/MarkMpn.Sql4Cds.Engine/Ado/Sql4CdsError.cs
@@ -138,6 +138,12 @@ internal static Sql4CdsError InvalidLengthOrPrecision(SqlDataTypeReference type)
             return Create(1001, type, (SqlInt32)type.StartLine, (SqlInt32)precision);
         }
 
+        internal static Sql4CdsError InvalidScale(SqlDataTypeReference type, int scaleParamIndex)
+        {
+            var precision = Int32.Parse(type.Parameters[scaleParamIndex].Value);
+            return Create(1002, type, (SqlInt32)type.StartLine, (SqlInt32)precision);
+        }
+
         internal static Sql4CdsError ArithmeticOverflow(DataTypeReference sourceType, DataTypeReference targetType, TSqlFragment fragment)
         {
             return Create(8115, fragment, GetTypeName(sourceType), GetTypeName(targetType));
@@ -228,6 +234,11 @@ internal static Sql4CdsError ConversionFailed(DataTypeReference sourceType, Lite
             return Create(245, sourceValue, Collation.USEnglish.ToSqlString(GetTypeName(sourceType)), (SqlInt32)sourceValue.Value.Length, Collation.USEnglish.ToSqlString(sourceValue.Value), Collation.USEnglish.ToSqlString(GetTypeName(targetType)));
         }
 
+        internal static Sql4CdsError ConversionOutOfRange(DataTypeReference sourceType, DataTypeReference targetType)
+        {
+            return Create(242, sourceType, Collation.USEnglish.ToSqlString(GetTypeName(sourceType)), Collation.USEnglish.ToSqlString(GetTypeName(targetType)));
+        }
+
         internal static Sql4CdsError CollationConflict(TSqlFragment fragment, Collation source, Collation target, string operationName)
         {
             return Create(468, fragment, (SqlInt32)(source?.Name.Length ?? 0), Collation.USEnglish.ToSqlString(source?.Name), (SqlInt32)(target?.Name.Length ?? 0), Collation.USEnglish.ToSqlString(target?.Name), Collation.USEnglish.ToSqlString(operationName));
@@ -780,6 +791,26 @@ internal static Sql4CdsError InvalidProcedureParameterType(TSqlFragment fragment
             return Create(214, fragment, parameter, type);
         }
 
+        internal static Sql4CdsError InvalidDatePart(TSqlFragment fragment, string part, string function, DataTypeReference dataType)
+        {
+            return Create(9810, fragment, (SqlInt32)part.Length, Collation.USEnglish.ToSqlString(part), (SqlInt32)function.Length, Collation.USEnglish.ToSqlString(function), Collation.USEnglish.ToSqlString(GetTypeName(dataType)));
+        }
+
+        internal static Sql4CdsError AdditionOverflow(TSqlFragment fragment, DataTypeReference type)
+        {
+            return Create(517, fragment, Collation.USEnglish.ToSqlString(GetTypeName(type)));
+        }
+
+        internal static Sql4CdsError UnsupportedDatePart(TSqlFragment fragment, string part, string function)
+        {
+            return Create(9806, fragment, (SqlInt32)part.Length, Collation.USEnglish.ToSqlString(part), (SqlInt32)function.Length, Collation.USEnglish.ToSqlString(function));
+        }
+
+        internal static Sql4CdsError InvalidDateFormat(TSqlFragment fragment, string format)
+        {
+            return Create(2741, fragment, (SqlInt32)format.Length, Collation.USEnglish.ToSqlString(format));
+        }
+
         private static string GetTypeName(DataTypeReference type)
         {
             if (type is SqlDataTypeReference sqlType)
diff --git a/MarkMpn.Sql4Cds.Engine/Ado/Sql4CdsParameter.cs b/MarkMpn.Sql4Cds.Engine/Ado/Sql4CdsParameter.cs
index 5dd71eef..de985b64 100644
--- a/MarkMpn.Sql4Cds.Engine/Ado/Sql4CdsParameter.cs
+++ b/MarkMpn.Sql4Cds.Engine/Ado/Sql4CdsParameter.cs
@@ -187,7 +187,7 @@ internal DataTypeReference GetDataType()
                         break;
 
                     case DbType.DateTimeOffset:
-                        _dataType = DataTypeHelpers.DateTimeOffset;
+                        _dataType = DataTypeHelpers.DateTimeOffset(7);
                         break;
 
                     case DbType.Decimal:
diff --git a/MarkMpn.Sql4Cds.Engine/DataTypeHelpers.cs b/MarkMpn.Sql4Cds.Engine/DataTypeHelpers.cs
index e01ddc69..1779d63c 100644
--- a/MarkMpn.Sql4Cds.Engine/DataTypeHelpers.cs
+++ b/MarkMpn.Sql4Cds.Engine/DataTypeHelpers.cs
@@ -51,7 +51,10 @@ public static SqlDataTypeReference DateTime2(short scale)
             return new SqlDataTypeReference { SqlDataTypeOption = SqlDataTypeOption.DateTime2, Parameters = { new IntegerLiteral { Value = scale.ToString(CultureInfo.InvariantCulture) } } };
         }
 
-        public static SqlDataTypeReference DateTimeOffset { get; } = new SqlDataTypeReference { SqlDataTypeOption = SqlDataTypeOption.DateTimeOffset };
+        public static SqlDataTypeReference DateTimeOffset(short scale)
+        {
+            return new SqlDataTypeReference { SqlDataTypeOption = SqlDataTypeOption.DateTimeOffset, Parameters = { new IntegerLiteral { Value = scale.ToString(CultureInfo.InvariantCulture) } } };
+        }
 
         public static SqlDataTypeReference Decimal(short precision, short scale)
         {
@@ -418,12 +421,10 @@ public static short GetScale(this DataTypeReference type, short invalidValue = 0
                 case SqlDataTypeOption.DateTime:
                     return 3;
 
-                case SqlDataTypeOption.DateTimeOffset:
-                    return 7;
-
                 case SqlDataTypeOption.SmallDateTime:
                     return 0;
 
+                case SqlDataTypeOption.DateTimeOffset:
                 case SqlDataTypeOption.DateTime2:
                 case SqlDataTypeOption.Time:
                     if (dataType.Parameters.Count == 0 ||
diff --git a/MarkMpn.Sql4Cds.Engine/ExecutionPlan/Aggregate.cs b/MarkMpn.Sql4Cds.Engine/ExecutionPlan/Aggregate.cs
index af423080..a2fe0790 100644
--- a/MarkMpn.Sql4Cds.Engine/ExecutionPlan/Aggregate.cs
+++ b/MarkMpn.Sql4Cds.Engine/ExecutionPlan/Aggregate.cs
@@ -92,10 +92,10 @@ public AggregateFunction(Func<object> selector)
         /// </summary>
         /// <param name="state">The current state of the aggregation</param>
         /// <returns>The new state of the aggregation</returns>
-        public virtual void NextRecord(object state)
+        public virtual void NextRecord(object state, ExpressionExecutionContext context)
         {
             var value = _selector();
-            Update(value, state);
+            Update(value, context, state);
         }
 
         /// <summary>
@@ -103,10 +103,10 @@ public virtual void NextRecord(object state)
         /// </summary>
         /// <param name="state">The current state of the aggregation</param>
         /// <returns>The new state of the aggregation</returns>
-        public virtual void NextPartition(object state)
+        public virtual void NextPartition(object state, ExpressionExecutionContext context)
         {
             var value = _selector();
-            UpdatePartition(value, state);
+            UpdatePartition(value, context, state);
         }
 
         /// <summary>
@@ -114,14 +114,14 @@ public virtual void NextPartition(object state)
         /// </summary>
         /// <param name="value"></param>
         /// <param name="state">The current state of the aggregation</param>
-        protected abstract void Update(object value, object state);
+        protected abstract void Update(object value, ExpressionExecutionContext context, object state);
 
         /// <summary>
         /// Updates the aggregation state based on a value extracted from the partition <see cref="Entity"/>
         /// </summary>
         /// <param name="value"></param>
         /// <param name="state">The current state of the aggregation</param>
-        protected abstract void UpdatePartition(object value, object state);
+        protected abstract void UpdatePartition(object value, ExpressionExecutionContext context, object state);
 
         /// <summary>
         /// Returns the current value of this aggregation
@@ -184,20 +184,20 @@ public Average(Func<object> selector, DataTypeReference sourceType, DataTypeRefe
             _count = new CountColumn(selector);
         }
 
-        public override void NextRecord(object state)
+        public override void NextRecord(object state, ExpressionExecutionContext context)
         {
             var s = (State)state;
 
-            _sum.NextRecord(s.SumState);
-            _count.NextRecord(s.CountState);
+            _sum.NextRecord(s.SumState, context);
+            _count.NextRecord(s.CountState, context);
         }
 
-        protected override void Update(object value, object state)
+        protected override void Update(object value, ExpressionExecutionContext context, object state)
         {
             throw new NotImplementedException();
         }
 
-        protected override void UpdatePartition(object value, object state)
+        protected override void UpdatePartition(object value, ExpressionExecutionContext context, object state)
         {
             throw new InvalidOperationException();
         }
@@ -253,13 +253,13 @@ public Count(Func<object> selector) : base(selector)
         {
         }
 
-        protected override void Update(object value, object state)
+        protected override void Update(object value, ExpressionExecutionContext context, object state)
         {
             var s = (State)state;
             s.Value = s.Value + 1;
         }
 
-        protected override void UpdatePartition(object value, object state)
+        protected override void UpdatePartition(object value, ExpressionExecutionContext context, object state)
         {
             var s = (State)state;
             s.Value = s.Value + (SqlInt32)value;
@@ -297,7 +297,7 @@ public CountColumn(Func<object> selector) : base(selector)
         {
         }
 
-        protected override void Update(object value, object state)
+        protected override void Update(object value, ExpressionExecutionContext context, object state)
         {
             if (value == null || (value is INullable nullable && nullable.IsNull))
                 return;
@@ -306,7 +306,7 @@ protected override void Update(object value, object state)
             s.Value = s.Value + 1;
         }
 
-        protected override void UpdatePartition(object value, object state)
+        protected override void UpdatePartition(object value, ExpressionExecutionContext context, object state)
         {
             var s = (State)state;
             s.Value = s.Value + (SqlInt32)value;
@@ -350,7 +350,7 @@ public Max(Func<object> selector, DataTypeReference type) : base(selector)
             Type = type;
         }
 
-        protected override void Update(object value, object state)
+        protected override void Update(object value, ExpressionExecutionContext context, object state)
         {
             if (value == null || (value is INullable nullable && nullable.IsNull))
                 return;
@@ -363,9 +363,9 @@ protected override void Update(object value, object state)
                 s.Value = cmp;
         }
 
-        protected override void UpdatePartition(object value, object state)
+        protected override void UpdatePartition(object value, ExpressionExecutionContext context, object state)
         {
-            Update(value, state);
+            Update(value, context, state);
         }
 
         public override object GetValue(object state)
@@ -406,7 +406,7 @@ public Min(Func<object> selector, DataTypeReference type) : base(selector)
             Type = type;
         }
 
-        protected override void Update(object value, object state)
+        protected override void Update(object value, ExpressionExecutionContext context, object state)
         {
             if (value == null || (value is INullable nullable && nullable.IsNull))
                 return;
@@ -420,9 +420,9 @@ protected override void Update(object value, object state)
                 s.Value = cmp;
         }
 
-        protected override void UpdatePartition(object value, object state)
+        protected override void UpdatePartition(object value, ExpressionExecutionContext context, object state)
         {
-            Update(value, state);
+            Update(value, context, state);
         }
 
         public override object GetValue(object state)
@@ -454,7 +454,7 @@ class State
         }
 
         private readonly SqlDataTypeOption _type;
-        private readonly Func<object, object> _valueSelector;
+        private readonly Func<object, ExpressionExecutionContext, object> _valueSelector;
 
         /// <summary>
         /// Creates a new <see cref="Sum"/>
@@ -467,15 +467,16 @@ public Sum(Func<object> selector, DataTypeReference sourceType, DataTypeReferenc
             _type = ((SqlDataTypeReference)returnType).SqlDataTypeOption;
 
             var valueParam = Expression.Parameter(typeof(object));
+            var contextParam = Expression.Parameter(typeof(ExpressionExecutionContext));
             var unboxed = Expression.Unbox(valueParam, sourceType.ToNetType(out _));
-            var conversion = SqlTypeConverter.Convert(unboxed, sourceType, returnType);
+            var conversion = SqlTypeConverter.Convert(unboxed, contextParam, sourceType, returnType);
             conversion = Expr.Box(conversion);
-            _valueSelector = (Func<object, object>) Expression.Lambda(conversion, valueParam).Compile();
+            _valueSelector = (Func<object, ExpressionExecutionContext, object>) Expression.Lambda(conversion, valueParam, contextParam).Compile();
         }
 
-        protected override void Update(object value, object state)
+        protected override void Update(object value, ExpressionExecutionContext context, object state)
         {
-            var d = (INullable)_valueSelector(value);
+            var d = (INullable)_valueSelector(value, context);
 
             if (d.IsNull)
                 return;
@@ -509,9 +510,9 @@ protected override void Update(object value, object state)
             }
         }
 
-        protected override void UpdatePartition(object value, object state)
+        protected override void UpdatePartition(object value, ExpressionExecutionContext context, object state)
         {
-            Update(value, state);
+            Update(value, context, state);
         }
 
         public override object GetValue(object state)
@@ -569,7 +570,7 @@ public First(Func<object> selector, DataTypeReference type) : base(selector)
             Type = type;
         }
 
-        protected override void Update(object value, object state)
+        protected override void Update(object value, ExpressionExecutionContext context, object state)
         {
             var s = (State)state;
             if (s.Done)
@@ -579,7 +580,7 @@ protected override void Update(object value, object state)
             s.Done = true;
         }
 
-        protected override void UpdatePartition(object value, object state)
+        protected override void UpdatePartition(object value, ExpressionExecutionContext context, object state)
         {
             throw new InvalidOperationException();
         }
@@ -611,7 +612,7 @@ public State()
             public SqlString Value { get; set; }
         }
 
-        private Func<object, SqlString> _valueSelector;
+        private Func<object, ExpressionExecutionContext, SqlString> _valueSelector;
 
         /// <summary>
         /// Creates a new <see cref="Sum"/>
@@ -622,17 +623,18 @@ public StringAgg(Func<object> selector, DataTypeReference sourceType, DataTypeRe
             Type = returnType;
 
             var valueParam = Expression.Parameter(typeof(object));
+            var contextParam = Expression.Parameter(typeof(ExpressionExecutionContext));
             var unboxed = Expression.Unbox(valueParam, sourceType.ToNetType(out _));
-            var conversion = SqlTypeConverter.Convert(unboxed, sourceType, returnType);
+            var conversion = SqlTypeConverter.Convert(unboxed, contextParam, sourceType, returnType);
             conversion = Expr.Convert(conversion, typeof(SqlString));
-            _valueSelector = (Func<object, SqlString>)Expression.Lambda(conversion, valueParam).Compile();
+            _valueSelector = (Func<object, ExpressionExecutionContext, SqlString>)Expression.Lambda(conversion, valueParam, contextParam).Compile();
         }
 
-        protected override void Update(object value, object state)
+        protected override void Update(object value, ExpressionExecutionContext context, object state)
         {
             var s = (State)state;
 
-            var str = _valueSelector(value);
+            var str = _valueSelector(value, context);
 
             if (str.IsNull)
                 return;
@@ -643,7 +645,7 @@ protected override void Update(object value, object state)
                 s.Value += Separator + str;
         }
 
-        protected override void UpdatePartition(object value, object state)
+        protected override void UpdatePartition(object value, ExpressionExecutionContext context, object state)
         {
             throw new InvalidOperationException();
         }
@@ -687,21 +689,21 @@ public DistinctAggregate(AggregateFunction func, Func<object> selector) : base(s
 
         public override DataTypeReference Type => _func.Type;
 
-        public override void NextRecord(object state)
+        public override void NextRecord(object state, ExpressionExecutionContext context)
         {
             var value = _selector();
             var s = (State)state;
 
             if (s.Distinct.Add(value))
-                _func.NextRecord(s.InnerState);
+                _func.NextRecord(s.InnerState, context);
         }
 
-        protected override void UpdatePartition(object value, object state)
+        protected override void UpdatePartition(object value, ExpressionExecutionContext context, object state)
         {
             throw new InvalidOperationException();
         }
 
-        protected override void Update(object value, object state)
+        protected override void Update(object value, ExpressionExecutionContext context, object state)
         {
             throw new NotImplementedException();
         }
diff --git a/MarkMpn.Sql4Cds.Engine/ExecutionPlan/AssignVariablesNode.cs b/MarkMpn.Sql4Cds.Engine/ExecutionPlan/AssignVariablesNode.cs
index af59ef61..feebab8f 100644
--- a/MarkMpn.Sql4Cds.Engine/ExecutionPlan/AssignVariablesNode.cs
+++ b/MarkMpn.Sql4Cds.Engine/ExecutionPlan/AssignVariablesNode.cs
@@ -50,11 +50,14 @@ public override void Execute(NodeExecutionContext context, out int recordsAffect
 
                 var entities = GetDmlSourceEntities(context, out var schema);
                 var valueAccessors = CompileValueAccessors(schema, entities, context.ParameterTypes);
+                var eec = new ExpressionExecutionContext(context);
 
                 foreach (var entity in entities)
                 {
+                    eec.Entity = entity;
+
                     foreach (var variable in Variables)
-                        context.ParameterValues[variable.VariableName] = (INullable)valueAccessors[variable.VariableName](entity);
+                        context.ParameterValues[variable.VariableName] = (INullable)valueAccessors[variable.VariableName](eec);
 
                     count++;
                 }
@@ -74,10 +77,10 @@ public override void Execute(NodeExecutionContext context, out int recordsAffect
         /// <param name="attributes">The attributes in the target metadata</param>
         /// <param name="dateTimeKind">The time zone that datetime values are supplied in</param>
         /// <returns></returns>
-        protected Dictionary<string, Func<Entity, object>> CompileValueAccessors(INodeSchema schema, List<Entity> entities, IDictionary<string, DataTypeReference> variableTypes)
+        protected Dictionary<string, Func<ExpressionExecutionContext, object>> CompileValueAccessors(INodeSchema schema, List<Entity> entities, IDictionary<string, DataTypeReference> variableTypes)
         {
-            var valueAccessors = new Dictionary<string, Func<Entity, object>>();
-            var entityParam = Expression.Parameter(typeof(Entity));
+            var valueAccessors = new Dictionary<string, Func<ExpressionExecutionContext, object>>();
+            var contextParam = Expression.Parameter(typeof(ExpressionExecutionContext));
 
             foreach (var mapping in Variables)
             {
@@ -94,7 +97,8 @@ protected Dictionary<string, Func<Entity, object>> CompileValueAccessors(INodeSc
 
                 var destNetType = destSqlType.ToNetType(out _);
 
-                var expr = (Expression)Expression.Property(entityParam, typeof(Entity).GetCustomAttribute<DefaultMemberAttribute>().MemberName, Expression.Constant(sourceColumnName));
+                var entity = Expression.Property(contextParam, nameof(ExpressionExecutionContext.Entity));
+                var expr = (Expression)Expression.Property(entity, typeof(Entity).GetCustomAttribute<DefaultMemberAttribute>().MemberName, Expression.Constant(sourceColumnName));
                 var originalExpr = expr;
 
                 if (sourceSqlType.IsSameAs(DataTypeHelpers.Int) && !SqlTypeConverter.CanChangeTypeExplicit(sourceSqlType, destSqlType) && entities.All(e => ((SqlInt32)e[sourceColumnName]).IsNull))
@@ -108,12 +112,12 @@ protected Dictionary<string, Func<Entity, object>> CompileValueAccessors(INodeSc
                     expr = Expression.Convert(expr, sourceSqlType.ToNetType(out _));
 
                     // Convert to destination SQL type
-                    expr = SqlTypeConverter.Convert(expr, sourceSqlType, destSqlType);
+                    expr = SqlTypeConverter.Convert(expr, contextParam, sourceSqlType, destSqlType);
                 }
 
                 expr = Expr.Box(expr);
 
-                valueAccessors[destVariableName] = Expression.Lambda<Func<Entity, object>>(expr, entityParam).Compile();
+                valueAccessors[destVariableName] = Expression.Lambda<Func<ExpressionExecutionContext, object>>(expr, contextParam).Compile();
             }
 
             return valueAccessors;
diff --git a/MarkMpn.Sql4Cds.Engine/ExecutionPlan/BaseDataNode.cs b/MarkMpn.Sql4Cds.Engine/ExecutionPlan/BaseDataNode.cs
index 05e76a3a..bedb2dad 100644
--- a/MarkMpn.Sql4Cds.Engine/ExecutionPlan/BaseDataNode.cs
+++ b/MarkMpn.Sql4Cds.Engine/ExecutionPlan/BaseDataNode.cs
@@ -387,40 +387,8 @@ private bool TranslateFetchXMLCriteria(NodeCompilationContext context, DataSourc
                 }
 
                 // Select the correct FetchXML operator
-                @operator op;
-
-                switch (type)
-                {
-                    case BooleanComparisonType.Equals:
-                    case BooleanComparisonType.IsNotDistinctFrom:
-                        op = @operator.eq;
-                        break;
-
-                    case BooleanComparisonType.GreaterThan:
-                        op = @operator.gt;
-                        break;
-
-                    case BooleanComparisonType.GreaterThanOrEqualTo:
-                        op = @operator.ge;
-                        break;
-
-                    case BooleanComparisonType.LessThan:
-                        op = @operator.lt;
-                        break;
-
-                    case BooleanComparisonType.LessThanOrEqualTo:
-                        op = @operator.le;
-                        break;
-
-                    case BooleanComparisonType.NotEqualToBrackets:
-                    case BooleanComparisonType.NotEqualToExclamation:
-                    case BooleanComparisonType.IsDistinctFrom:
-                        op = @operator.ne;
-                        break;
-
-                    default:
-                        throw new NotSupportedQueryFragmentException(Sql4CdsError.SyntaxError(comparison)) { Suggestion = "Unsupported comparison type" };
-                }
+                if (!type.TryConvertToFetchXml(out var op))
+                    throw new NotSupportedQueryFragmentException(Sql4CdsError.SyntaxError(comparison)) { Suggestion = "Unsupported comparison type" };
 
                 // Find the entity that the condition applies to, which may be different to the entity that the condition FetchXML element will be 
                 // added within
@@ -741,7 +709,7 @@ private bool TranslateFetchXMLCriteria(NodeCompilationContext context, DataSourc
                 if (inPred.Subquery != null)
                     return false;
 
-                if (!inPred.Values.All(v => v is Literal))
+                if (!inPred.Values.All(v => v is ValueExpression))
                     return false;
 
                 var columnName = inCol.GetColumnName();
@@ -764,7 +732,7 @@ private bool TranslateFetchXMLCriteria(NodeCompilationContext context, DataSourc
 
                 var meta = dataSource.Metadata[entityName];
 
-                return TranslateFetchXMLCriteriaWithVirtualAttributes(context, meta, entityAlias, attrName, null, op, inPred.Values.Cast<Literal>().ToArray(), dataSource, targetEntityAlias, items, out condition, out filter);
+                return TranslateFetchXMLCriteriaWithVirtualAttributes(context, meta, entityAlias, attrName, null, op, inPred.Values.Cast<ValueExpression>().ToArray(), dataSource, targetEntityAlias, items, out condition, out filter);
             }
 
             if (criteria is BooleanIsNullExpression isNull)
diff --git a/MarkMpn.Sql4Cds.Engine/ExecutionPlan/BaseDmlNode.cs b/MarkMpn.Sql4Cds.Engine/ExecutionPlan/BaseDmlNode.cs
index e404fcc4..30aca68c 100644
--- a/MarkMpn.Sql4Cds.Engine/ExecutionPlan/BaseDmlNode.cs
+++ b/MarkMpn.Sql4Cds.Engine/ExecutionPlan/BaseDmlNode.cs
@@ -181,7 +181,7 @@ private int GetMaxDOP(NodeCompilationContext context, IList<OptimizerHint> query
             if (DataSource == null)
                 return 1;
 
-            if (!context.DataSources.TryGetValue(DataSource, out var dataSource))
+            if (!context.Session.DataSources.TryGetValue(DataSource, out var dataSource))
                 throw new NotSupportedQueryFragmentException("Unknown datasource");
 
             return ParallelismHelper.GetMaxDOP(dataSource, context, queryHints);
@@ -235,6 +235,66 @@ private bool GetContinueOnError(NodeCompilationContext context, IList<OptimizerH
             return continueOnError;
         }
 
+        protected void FoldIdsToConstantScan(NodeCompilationContext context, IList<OptimizerHint> hints, string logicalName, string[] requiredColumns)
+        {
+            if (hints != null && hints.OfType<UseHintList>().Any(hint => hint.Hints.Any(s => s.Value.Equals("NO_DIRECT_DML", StringComparison.OrdinalIgnoreCase))))
+                return;
+
+            // Work out the fields that we should use as the primary key for these records.
+            var dataSource = context.Session.DataSources[DataSource];
+            var targetMetadata = dataSource.Metadata[logicalName];
+            var keyAttributes = new[] { targetMetadata.PrimaryIdAttribute };
+
+            if (targetMetadata.LogicalName == "listmember")
+            {
+                keyAttributes = new[] { "listid", "entityid" };
+            }
+            else if (targetMetadata.IsIntersect == true)
+            {
+                var relationship = targetMetadata.ManyToManyRelationships.Single();
+                keyAttributes = new[] { relationship.Entity1IntersectAttribute, relationship.Entity2IntersectAttribute };
+            }
+            else if (targetMetadata.DataProviderId == DataProviders.ElasticDataProvider)
+            {
+                // Elastic tables need the partitionid as part of the primary key
+                keyAttributes = new[] { targetMetadata.PrimaryIdAttribute, "partitionid" };
+            }
+            else if (targetMetadata.LogicalName == "activitypointer")
+            {
+                // Can't do DML operations on base activitypointer table, need to read the record to
+                // find the concrete activity type.
+                return;
+            }
+
+            // Skip any ComputeScalar node that is being used to generate additional values,
+            // unless they reference additional values in the data source
+            var compute = Source as ComputeScalarNode;
+
+            if (compute != null)
+            {
+                if (compute.Columns.Any(c => c.Value.GetColumns().Except(keyAttributes).Any()))
+                    return;
+
+                // Ignore any columns being created by the ComputeScalar node
+                foreach (var col in compute.Columns)
+                    requiredColumns = requiredColumns.Except(new[] { col.Key }).ToArray();
+            }
+
+            if ((compute?.Source ?? Source) is FetchXmlScan fetch)
+            {
+                var folded = fetch.FoldDmlSource(context, hints, logicalName, requiredColumns, keyAttributes);
+
+                if (compute != null)
+                    compute.Source = folded;
+                else
+                    Source = folded;
+            }
+            else if (Source is SqlNode sql)
+            {
+                Source = sql.FoldDmlSource(context, hints, logicalName, requiredColumns, keyAttributes);
+            }
+        }
+
         /// <summary>
         /// Changes the name of source columns
         /// </summary>
@@ -269,7 +329,7 @@ protected List<Entity> GetDmlSourceEntities(NodeExecutionContext context, out IN
                 var dataTable = new DataTable();
                 var schemaTable = dataReader.GetSchemaTable();
                 var columnTypes = new ColumnList();
-                var targetDataSource = DataSource == null ? context.PrimaryDataSource : context.DataSources[DataSource];
+                var targetDataSource = DataSource == null ? context.PrimaryDataSource : context.Session.DataSources[DataSource];
 
                 for (var i = 0; i < schemaTable.Rows.Count; i++)
                 {
@@ -297,7 +357,7 @@ protected List<Entity> GetDmlSourceEntities(NodeExecutionContext context, out IN
                         case "smalldatetime": colSqlType = DataTypeHelpers.SmallDateTime; break;
                         case "date": colSqlType = DataTypeHelpers.Date; break;
                         case "time": colSqlType = DataTypeHelpers.Time(scale); break;
-                        case "datetimeoffset": colSqlType = DataTypeHelpers.DateTimeOffset; break;
+                        case "datetimeoffset": colSqlType = DataTypeHelpers.DateTimeOffset(scale); break;
                         case "datetime2": colSqlType = DataTypeHelpers.DateTime2(scale); break;
                         case "decimal": colSqlType = DataTypeHelpers.Decimal(precision, scale); break;
                         case "numeric": colSqlType = DataTypeHelpers.Decimal(precision, scale); break;
@@ -384,13 +444,14 @@ protected List<Entity> GetDmlSourceEntities(NodeExecutionContext context, out IN
         /// <param name="dateTimeKind">The time zone that datetime values are supplied in</param>
         /// <param name="entities">The records that are being mapped</param>
         /// <returns></returns>
-        protected Dictionary<string, Func<Entity, object>> CompileColumnMappings(DataSource dataSource, string logicalName, IDictionary<string,string> mappings, INodeSchema schema, DateTimeKind dateTimeKind, List<Entity> entities)
+        protected Dictionary<string, Func<ExpressionExecutionContext, object>> CompileColumnMappings(DataSource dataSource, string logicalName, IDictionary<string,string> mappings, INodeSchema schema, DateTimeKind dateTimeKind, List<Entity> entities)
         {
             var metadata = dataSource.Metadata[logicalName];
             var attributes = metadata.Attributes.ToDictionary(a => a.LogicalName, StringComparer.OrdinalIgnoreCase);
 
-            var attributeAccessors = new Dictionary<string, Func<Entity, object>>();
-            var entityParam = Expression.Parameter(typeof(Entity));
+            var attributeAccessors = new Dictionary<string, Func<ExpressionExecutionContext, object>>();
+            var contextParam = Expression.Parameter(typeof(ExpressionExecutionContext));
+            var entityParam = Expression.Property(contextParam, nameof(ExpressionExecutionContext.Entity));
 
             foreach (var mapping in mappings)
             {
@@ -438,7 +499,7 @@ protected Dictionary<string, Func<Entity, object>> CompileColumnMappings(DataSou
                         {
                             convertedExpr = expr;
                             expr = originalExpr;
-                            convertedExpr = SqlTypeConverter.Convert(convertedExpr, typeof(EntityReference));
+                            convertedExpr = SqlTypeConverter.Convert(convertedExpr, contextParam, typeof(EntityReference));
                         }
                         else if (sourceSqlType == DataTypeHelpers.ImplicitIntForNullLiteral)
                         {
@@ -472,13 +533,13 @@ protected Dictionary<string, Func<Entity, object>> CompileColumnMappings(DataSou
                                 {
                                     // Normally we want to specify the target type as a logical name
                                     var stringType = DataTypeHelpers.NVarChar(MetadataExtensions.EntityLogicalNameMaxLength, dataSource.DefaultCollation, CollationLabel.Implicit);
-                                    targetExpr = SqlTypeConverter.Convert(targetExpr, sourceTargetType, stringType);
-                                    targetExpr = SqlTypeConverter.Convert(targetExpr, typeof(string));
+                                    targetExpr = SqlTypeConverter.Convert(targetExpr, contextParam, sourceTargetType, stringType);
+                                    targetExpr = SqlTypeConverter.Convert(targetExpr, contextParam, typeof(string));
                                 }
                             }
 
-                            convertedExpr = SqlTypeConverter.Convert(expr, sourceSqlType, DataTypeHelpers.UniqueIdentifier);
-                            convertedExpr = SqlTypeConverter.Convert(convertedExpr, typeof(Guid));
+                            convertedExpr = SqlTypeConverter.Convert(expr, contextParam, sourceSqlType, DataTypeHelpers.UniqueIdentifier);
+                            convertedExpr = SqlTypeConverter.Convert(convertedExpr, contextParam, typeof(Guid));
                             convertedExpr = Expression.New(
                                 typeof(EntityReference).GetConstructor(new[] { typeof(string), typeof(Guid) }),
                                 targetExpr,
@@ -490,8 +551,8 @@ protected Dictionary<string, Func<Entity, object>> CompileColumnMappings(DataSou
                         {
                             var partitionIdExpr = (Expression)Expression.Property(entityParam, typeof(Entity).GetCustomAttribute<DefaultMemberAttribute>().MemberName, Expression.Constant(partitionIdColumn));
                             partitionIdExpr = Expression.Convert(partitionIdExpr, schema.Schema[partitionIdColumn].Type.ToNetType(out _));
-                            partitionIdExpr = SqlTypeConverter.Convert(partitionIdExpr, schema.Schema[partitionIdColumn].Type, DataTypeHelpers.NVarChar(100, dataSource.DefaultCollation, CollationLabel.Implicit));
-                            partitionIdExpr = SqlTypeConverter.Convert(partitionIdExpr, typeof(string));
+                            partitionIdExpr = SqlTypeConverter.Convert(partitionIdExpr, contextParam, schema.Schema[partitionIdColumn].Type, DataTypeHelpers.NVarChar(100, dataSource.DefaultCollation, CollationLabel.Implicit));
+                            partitionIdExpr = SqlTypeConverter.Convert(partitionIdExpr, contextParam, typeof(string));
                             convertedExpr = Expr.Call(() => CreateElasticEntityReference(Expr.Arg<EntityReference>(), Expr.Arg<string>(), Expr.Arg<IAttributeMetadataCache>()), convertedExpr, partitionIdExpr, Expression.Constant(dataSource.Metadata));
                         }
 
@@ -505,11 +566,11 @@ protected Dictionary<string, Func<Entity, object>> CompileColumnMappings(DataSou
                         {
                             // Convert to destination SQL type - don't do this if we're converting from an EntityReference to a PartyList so
                             // we don't lose the entity name during the conversion via a string
-                            expr = SqlTypeConverter.Convert(expr, sourceSqlType, destSqlType, throwOnTruncate: true, table: logicalName, column: destAttributeName);
+                            expr = SqlTypeConverter.Convert(expr, contextParam, sourceSqlType, destSqlType, throwOnTruncate: true, table: logicalName, column: destAttributeName);
                         }
 
                         // Convert to final .NET SDK type
-                        convertedExpr = SqlTypeConverter.Convert(expr, destType);
+                        convertedExpr = SqlTypeConverter.Convert(expr, contextParam, destType);
                         
                         if (attr is EnumAttributeMetadata && !(attr is MultiSelectPicklistAttributeMetadata))
                         {
@@ -546,10 +607,10 @@ protected Dictionary<string, Func<Entity, object>> CompileColumnMappings(DataSou
                         convertedExpr);
 
                     if (expr.Type.IsValueType)
-                        expr = SqlTypeConverter.Convert(expr, typeof(object));
+                        expr = SqlTypeConverter.Convert(expr, contextParam, typeof(object));
                 }
 
-                attributeAccessors[destAttributeName] = Expression.Lambda<Func<Entity, object>>(expr, entityParam).Compile();
+                attributeAccessors[destAttributeName] = Expression.Lambda<Func<ExpressionExecutionContext, object>>(expr, contextParam).Compile();
             }
 
             return attributeAccessors;
diff --git a/MarkMpn.Sql4Cds.Engine/ExecutionPlan/BulkDeleteJobNode.cs b/MarkMpn.Sql4Cds.Engine/ExecutionPlan/BulkDeleteJobNode.cs
index af94d3d2..932a8a4c 100644
--- a/MarkMpn.Sql4Cds.Engine/ExecutionPlan/BulkDeleteJobNode.cs
+++ b/MarkMpn.Sql4Cds.Engine/ExecutionPlan/BulkDeleteJobNode.cs
@@ -53,7 +53,7 @@ public void Execute(NodeExecutionContext context, out int recordsAffected, out s
 
             try
             {
-                if (!context.DataSources.TryGetValue(DataSource, out var dataSource))
+                if (!context.Session.DataSources.TryGetValue(DataSource, out var dataSource))
                     throw new QueryExecutionException("Missing datasource " + DataSource);
 
                 Microsoft.Xrm.Sdk.Query.QueryExpression query;
diff --git a/MarkMpn.Sql4Cds.Engine/ExecutionPlan/DeleteNode.cs b/MarkMpn.Sql4Cds.Engine/ExecutionPlan/DeleteNode.cs
index e7063661..8f24a378 100644
--- a/MarkMpn.Sql4Cds.Engine/ExecutionPlan/DeleteNode.cs
+++ b/MarkMpn.Sql4Cds.Engine/ExecutionPlan/DeleteNode.cs
@@ -74,7 +74,7 @@ public override IRootExecutionPlanNodeInternal[] FoldQuery(NodeCompilationContex
             if (result.Length != 1 || result[0] != this)
                 return result;
 
-            if (!context.DataSources.TryGetValue(DataSource, out var dataSource))
+            if (!context.Session.DataSources.TryGetValue(DataSource, out var dataSource))
                 throw new NotSupportedQueryFragmentException("Missing datasource " + DataSource);
 
             // Use bulk delete if requested & possible
@@ -92,6 +92,9 @@ Source is FetchXmlScan fetch &&
                 }
             }
 
+            // Replace a source query with a list of known IDs if possible
+            FoldIdsToConstantScan(context, hints, LogicalName, ColumnMappings.Values.ToArray());
+
             return new[] { this };
         }
 
@@ -114,12 +117,13 @@ public override void Execute(NodeExecutionContext context, out int recordsAffect
 
             try
             {
-                if (!context.DataSources.TryGetValue(DataSource, out var dataSource))
+                if (!context.Session.DataSources.TryGetValue(DataSource, out var dataSource))
                     throw new QueryExecutionException("Missing datasource " + DataSource);
 
                 List<Entity> entities;
                 EntityMetadata meta;
-                Dictionary<string, Func<Entity, object>> attributeAccessors;
+                Dictionary<string, Func<ExpressionExecutionContext, object>> attributeAccessors;
+                var eec = new ExpressionExecutionContext(context);
                 
                 using (_timer.Run())
                 {
@@ -163,7 +167,11 @@ public override void Execute(NodeExecutionContext context, out int recordsAffect
                         context.Options,
                         entities,
                         meta,
-                        entity => CreateDeleteRequest(meta, entity, attributeAccessors),
+                        entity =>
+                        {
+                            eec.Entity = entity;
+                            return CreateDeleteRequest(meta, eec, attributeAccessors);
+                        },
                         new OperationNames
                         {
                             InProgressUppercase = "Deleting",
@@ -188,14 +196,14 @@ public override void Execute(NodeExecutionContext context, out int recordsAffect
             }
         }
 
-        private OrganizationRequest CreateDeleteRequest(EntityMetadata meta, Entity entity, Dictionary<string,Func<Entity,object>> attributeAccessors)
+        private OrganizationRequest CreateDeleteRequest(EntityMetadata meta, ExpressionExecutionContext context, Dictionary<string,Func<ExpressionExecutionContext,object>> attributeAccessors)
         {
             if (meta.LogicalName == "principalobjectaccess")
             {
-                var objectId = (Guid)attributeAccessors["objectid"](entity);
-                var objectTypeCode = entity.GetAttributeValue<SqlString>(ColumnMappings["objecttypecode"]).Value;
-                var principalId = (Guid)attributeAccessors["principalid"](entity);
-                var principalTypeCode = entity.GetAttributeValue<SqlString>(ColumnMappings["principaltypecode"]).Value;
+                var objectId = (Guid)attributeAccessors["objectid"](context);
+                var objectTypeCode = context.Entity.GetAttributeValue<SqlString>(ColumnMappings["objecttypecode"]).Value;
+                var principalId = (Guid)attributeAccessors["principalid"](context);
+                var principalTypeCode = context.Entity.GetAttributeValue<SqlString>(ColumnMappings["principaltypecode"]).Value;
 
                 return new RevokeAccessRequest
                 {
@@ -209,16 +217,16 @@ private OrganizationRequest CreateDeleteRequest(EntityMetadata meta, Entity enti
             {
                 return new RemoveMemberListRequest
                 {
-                    ListId = (Guid)attributeAccessors["listid"](entity),
-                    EntityId = (Guid)attributeAccessors["entityid"](entity)
+                    ListId = (Guid)attributeAccessors["listid"](context),
+                    EntityId = (Guid)attributeAccessors["entityid"](context)
                 };
             }
             else if (meta.IsIntersect == true)
             {
                 var relationship = meta.ManyToManyRelationships.Single();
 
-                var targetId = (Guid)attributeAccessors[relationship.Entity1IntersectAttribute](entity);
-                var relatedId = (Guid)attributeAccessors[relationship.Entity2IntersectAttribute](entity);
+                var targetId = (Guid)attributeAccessors[relationship.Entity1IntersectAttribute](context);
+                var relatedId = (Guid)attributeAccessors[relationship.Entity2IntersectAttribute](context);
 
                 return new DisassociateRequest
                 {
@@ -228,7 +236,7 @@ private OrganizationRequest CreateDeleteRequest(EntityMetadata meta, Entity enti
                 };
             }
 
-            var id = (Guid)attributeAccessors[meta.PrimaryIdAttribute](entity);
+            var id = (Guid)attributeAccessors[meta.PrimaryIdAttribute](context);
             var req = new DeleteRequest
             {
                 Target = new EntityReference(LogicalName, id)
@@ -242,14 +250,14 @@ private OrganizationRequest CreateDeleteRequest(EntityMetadata meta, Entity enti
                     KeyAttributes =
                     {
                         [meta.PrimaryIdAttribute] = id,
-                        ["partitionid"] = attributeAccessors["partitionid"](entity)
+                        ["partitionid"] = attributeAccessors["partitionid"](context)
                     }
                 };
             }
 
             // Special case for activitypointer - need to set the specific activity type code
             if (LogicalName == "activitypointer")
-                req.Target.LogicalName = entity.GetAttributeValue<SqlString>(ColumnMappings["activitytypecode"]).Value;
+                req.Target.LogicalName = context.Entity.GetAttributeValue<SqlString>(ColumnMappings["activitytypecode"]).Value;
 
             return req;
         }
diff --git a/MarkMpn.Sql4Cds.Engine/ExecutionPlan/DistinctNode.cs b/MarkMpn.Sql4Cds.Engine/ExecutionPlan/DistinctNode.cs
index 15dc6bff..274b438c 100644
--- a/MarkMpn.Sql4Cds.Engine/ExecutionPlan/DistinctNode.cs
+++ b/MarkMpn.Sql4Cds.Engine/ExecutionPlan/DistinctNode.cs
@@ -96,7 +96,7 @@ public override IDataExecutionPlanNodeInternal FoldQuery(NodeCompilationContext
                 if (fetch.Entity.name == "audit" && Columns.Any(col => col.StartsWith(fetch.Alias.EscapeIdentifier() + ".objectid")))
                     return this;
 
-                var metadata = context.DataSources[fetch.DataSource].Metadata;
+                var metadata = context.Session.DataSources[fetch.DataSource].Metadata;
 
                 // Can't apply DISTINCT to partylist attributes
                 // https://github.com/MarkMpn/Sql4Cds/issues/528
diff --git a/MarkMpn.Sql4Cds.Engine/ExecutionPlan/ExecuteAsNode.cs b/MarkMpn.Sql4Cds.Engine/ExecutionPlan/ExecuteAsNode.cs
index e4ae0a11..99405697 100644
--- a/MarkMpn.Sql4Cds.Engine/ExecutionPlan/ExecuteAsNode.cs
+++ b/MarkMpn.Sql4Cds.Engine/ExecutionPlan/ExecuteAsNode.cs
@@ -75,7 +75,7 @@ public override void Execute(NodeExecutionContext context, out int recordsAffect
             {
                 using (_timer.Run())
                 {
-                    if (!context.DataSources.TryGetValue(DataSource, out var dataSource))
+                    if (!context.Session.DataSources.TryGetValue(DataSource, out var dataSource))
                         throw new QueryExecutionException("Missing datasource " + DataSource);
 
                     var entities = GetDmlSourceEntities(context, out var schema);
@@ -93,10 +93,11 @@ public override void Execute(NodeExecutionContext context, out int recordsAffect
                         throw new QueryExecutionException(Sql4CdsError.ImpersonationError(username), new ApplicationException("Ambiguous username"));
 
                     // Precompile mappings with type conversions
+                    var eec = new ExpressionExecutionContext(context) { Entity = entities[0] };
                     var attributeAccessors = CompileColumnMappings(dataSource, "systemuser", new Dictionary<string, string>(StringComparer.OrdinalIgnoreCase) { ["systemuserid"] = UserIdSource }, schema, DateTimeKind.Unspecified, entities);
                     var userIdAccessor = attributeAccessors["systemuserid"];
 
-                    var userId = (Guid)userIdAccessor(entities[0]);
+                    var userId = (Guid)userIdAccessor(eec);
 
                     PropertyInfo callerIdProp;
 
diff --git a/MarkMpn.Sql4Cds.Engine/ExecutionPlan/ExecuteMessageNode.cs b/MarkMpn.Sql4Cds.Engine/ExecutionPlan/ExecuteMessageNode.cs
index 05fcb19c..ba75b75b 100644
--- a/MarkMpn.Sql4Cds.Engine/ExecutionPlan/ExecuteMessageNode.cs
+++ b/MarkMpn.Sql4Cds.Engine/ExecutionPlan/ExecuteMessageNode.cs
@@ -136,7 +136,7 @@ public override IDataExecutionPlanNodeInternal FoldQuery(NodeCompilationContext
                     var expr = value.Value.Compile(expressionContext);
                     var sqlConversion = SqlTypeConverter.GetConversion(sourceSqlType, destSqlType);
                     var netConversion = SqlTypeConverter.GetConversion(destSqlType, destNetType);
-                    var conversion = (Func<ExpressionExecutionContext, object>) ((ExpressionExecutionContext ctx) => netConversion(sqlConversion(expr(ctx))));
+                    var conversion = (Func<ExpressionExecutionContext, object>) ((ExpressionExecutionContext ctx) => netConversion(sqlConversion(expr(ctx), ctx), ctx));
                     if (ValueTypes[value.Key] == typeof(Entity))
                     {
                         var conversionToString = conversion;
@@ -283,7 +283,7 @@ protected override IEnumerable<Entity> ExecuteInternal(NodeExecutionContext cont
         {
             PagesRetrieved = 0;
 
-            if (!context.DataSources.TryGetValue(DataSource, out var dataSource))
+            if (!context.Session.DataSources.TryGetValue(DataSource, out var dataSource))
                 throw new NotSupportedQueryFragmentException("Missing datasource " + DataSource);
 
             context.Options.Progress(0, $"Executing {MessageName}...");
diff --git a/MarkMpn.Sql4Cds.Engine/ExecutionPlan/ExpressionExtensions.cs b/MarkMpn.Sql4Cds.Engine/ExecutionPlan/ExpressionExtensions.cs
index 9bd47bde..edff418e 100644
--- a/MarkMpn.Sql4Cds.Engine/ExecutionPlan/ExpressionExtensions.cs
+++ b/MarkMpn.Sql4Cds.Engine/ExecutionPlan/ExpressionExtensions.cs
@@ -111,8 +111,8 @@ public static Func<ExpressionExecutionContext, bool> Compile(this BooleanExpress
 
         private static Expression ToExpression(this TSqlFragment expr, ExpressionCompilationContext context, bool createExpression, out ParameterExpression[] parameters, out DataTypeReference sqlType, out string cacheKey)
         {
-            var contextParam = createExpression ? Expression.Parameter(typeof(ExpressionExecutionContext)) : null;
-            var exprParam = createExpression ? Expression.Parameter(typeof(TSqlFragment)) : null;
+            var contextParam = Expression.Parameter(typeof(ExpressionExecutionContext));
+            var exprParam = Expression.Parameter(typeof(TSqlFragment));
 
             Expression expression;
 
@@ -334,17 +334,21 @@ private static Expression ToExpression(ColumnReferenceExpression col, Expression
             return Expression.Convert(expr, returnType);
         }
 
-        private static Expression ToExpression(IdentifierLiteral guid, ExpressionCompilationContext context, ParameterExpression contextParam, ParameterExpression exprParam, bool createExpression, out DataTypeReference sqlType, out string cacheKey)
+        private static Expression ToExpression(IdentifierLiteral id, ExpressionCompilationContext context, ParameterExpression contextParam, ParameterExpression exprParam, bool createExpression, out DataTypeReference sqlType, out string cacheKey)
         {
-            sqlType = DataTypeHelpers.UniqueIdentifier;
-            cacheKey = "<GuidLiteral>";
+            sqlType = DataTypeHelpers.VarChar(id.Value.Length, context.PrimaryDataSource.DefaultCollation, CollationLabel.CoercibleDefault);
+
+            cacheKey = $"<IdentifierLiteral({GetTypeKey(sqlType, false)})>";
 
             if (!createExpression)
                 return null;
 
-            return Expr.Call(
-                () => SqlGuid.Parse(Expr.Arg<string>()),
-                Expression.Property(Expression.Convert(exprParam, typeof(IdentifierLiteral)), nameof(IdentifierLiteral.Value)));
+            var value = Expression.Property(Expression.Convert(exprParam, typeof(IdentifierLiteral)), nameof(IdentifierLiteral.Value));
+
+            var expr = (Expression)Expression.Property(contextParam, nameof(ExpressionExecutionContext.PrimaryDataSource));
+            expr = Expression.Property(expr, nameof(DataSource.DefaultCollation));
+            expr = Expression.Call(expr, nameof(Collation.ToSqlString), Array.Empty<Type>(), value);
+            return expr;
         }
 
         private static Expression ToExpression(IntegerLiteral i, ExpressionCompilationContext context, ParameterExpression contextParam, ParameterExpression exprParam, bool createExpression, out DataTypeReference sqlType, out string cacheKey)
@@ -545,7 +549,7 @@ cmp.SecondExpression is FunctionCall func &&
             }
 
             if (!lhsType.IsSameAs(type))
-                lhs = createExpression ? SqlTypeConverter.Convert(lhs, lhsType, type) : null;
+                lhs = createExpression ? SqlTypeConverter.Convert(lhs, contextParam, lhsType, type) : null;
 
             if (!rhsType.IsSameAs(type))
             {
@@ -565,7 +569,7 @@ cmp.SecondExpression is StringLiteral str &&
                     };
                 }
 
-                rhs = createExpression ? SqlTypeConverter.Convert(rhs, rhsType, type) : null;
+                rhs = createExpression ? SqlTypeConverter.Convert(rhs, contextParam, rhsType, type) : null;
             }
 
             AssertCollationSensitive(type);
@@ -629,7 +633,7 @@ private static Expression ToExpression(DistinctPredicate distinct, ExpressionCom
             }
 
             if (!lhsType.IsSameAs(type))
-                lhs = createExpression ? SqlTypeConverter.Convert(lhs, lhsType, type) : null;
+                lhs = createExpression ? SqlTypeConverter.Convert(lhs, contextParam, lhsType, type) : null;
 
             if (!rhsType.IsSameAs(type))
             {
@@ -649,7 +653,7 @@ distinct.SecondExpression is StringLiteral str &&
                     };
                 }
 
-                rhs = createExpression ? SqlTypeConverter.Convert(rhs, rhsType, type) : null;
+                rhs = createExpression ? SqlTypeConverter.Convert(rhs, contextParam, rhsType, type) : null;
             }
 
             AssertCollationSensitive(type);
@@ -804,17 +808,17 @@ rhsSqlType is SqlDataTypeReference sqlRhsType &&
                 type = DataTypeHelpers.Decimal(p, s);
 
                 if (lhs.Type != typeof(SqlDecimal))
-                    lhs = SqlTypeConverter.Convert(lhs, lhsSqlType, DataTypeHelpers.Decimal(lhsSqlType.GetPrecision(), lhsSqlType.GetScale()));
+                    lhs = SqlTypeConverter.Convert(lhs, contextParam, lhsSqlType, DataTypeHelpers.Decimal(lhsSqlType.GetPrecision(), lhsSqlType.GetScale()));
                 if (rhs.Type != typeof(SqlDecimal))
-                    rhs = SqlTypeConverter.Convert(rhs, rhsSqlType, DataTypeHelpers.Decimal(rhsSqlType.GetPrecision(), rhsSqlType.GetScale()));
+                    rhs = SqlTypeConverter.Convert(rhs, contextParam, rhsSqlType, DataTypeHelpers.Decimal(rhsSqlType.GetPrecision(), rhsSqlType.GetScale()));
             }
             else
             {
                 if (!lhsSqlType.IsSameAs(type))
-                    lhs = SqlTypeConverter.Convert(lhs, lhsSqlType, type);
+                    lhs = SqlTypeConverter.Convert(lhs, contextParam, lhsSqlType, type);
 
                 if (!rhsSqlType.IsSameAs(type))
-                    rhs = SqlTypeConverter.Convert(rhs, rhsSqlType, type);
+                    rhs = SqlTypeConverter.Convert(rhs, contextParam, rhsSqlType, type);
             }
 
             sqlType = null;
@@ -954,12 +958,13 @@ private static MethodInfo GetMethod(FunctionCall func, ExpressionCompilationCont
             var paramExpressionsWithType = func.Parameters
                 .Select((param, index) =>
                 {
-                    // Special case for DATEPART / DATEDIFF / DATEADD - first parameter looks like a field but is actually an identifier
+                    // Special case for DATEPART / DATEDIFF / DATEADD / DATETRUNC - first parameter looks like a field but is actually an identifier
                     if (index == 0 &&
                         (
                             func.FunctionName.Value.Equals("DATEPART", StringComparison.OrdinalIgnoreCase) ||
                             func.FunctionName.Value.Equals("DATEDIFF", StringComparison.OrdinalIgnoreCase) ||
-                            func.FunctionName.Value.Equals("DATEADD", StringComparison.OrdinalIgnoreCase)
+                            func.FunctionName.Value.Equals("DATEADD", StringComparison.OrdinalIgnoreCase) ||
+                            func.FunctionName.Value.Equals("DATETRUNC", StringComparison.OrdinalIgnoreCase)
                         ))
                     {
                         // Check parameter is an expected datepart value
@@ -969,16 +974,9 @@ private static MethodInfo GetMethod(FunctionCall func, ExpressionCompilationCont
                             ex = new NotSupportedQueryFragmentException(Sql4CdsError.InvalidParameter(param, 1, "datepart"));
                             col = null;
                         }
-                        else
+                        else if (!ExpressionFunctions.TryParseDatePart(col.MultiPartIdentifier.Identifiers.Single().Value, out _))
                         {
-                            try
-                            {
-                                ExpressionFunctions.DatePartToInterval(col.MultiPartIdentifier.Identifiers.Single().Value);
-                            }
-                            catch
-                            {
-                                ex = new NotSupportedQueryFragmentException(Sql4CdsError.InvalidOptionValue(param, "datepart"));
-                            }
+                            ex = new NotSupportedQueryFragmentException(Sql4CdsError.InvalidOptionValue(param, "datepart"));
                         }
 
                         if (ex != null)
@@ -1010,6 +1008,46 @@ private static MethodInfo GetMethod(FunctionCall func, ExpressionCompilationCont
                     }
                     
                     var paramExpr = func.InvokeSubExpression(x => x.Parameters[index], (x, i) => x.Parameters[i], index, context, contextParam, exprParam, createExpression, out var paramType, out var paramCacheKey, out var paramException);
+
+                    // Special case for DATEPART - second parameter can accept any datetime family type. Function is implemented
+                    // to accept datetimeoffset for highest precision, but also needs to accept numeric types which can't be converted
+                    // to datetimeoffset. Convert them to datetime first
+                    if (index == 1 &&
+                        func.FunctionName.Value.Equals("DATEPART", StringComparison.OrdinalIgnoreCase) &&
+                        paramType is SqlDataTypeReference datePartParamSqlType &&
+                        datePartParamSqlType.SqlDataTypeOption.IsNumeric())
+                    {
+                        var dateTimeType = (DataTypeReference) DataTypeHelpers.DateTime;
+                        paramExpr = Convert(context, contextParam, paramExpr, paramType, paramCacheKey, ref dateTimeType, null, null, null, func.Parameters[index], "IMPLICIT", out paramCacheKey);
+                        paramType = dateTimeType;
+                    }
+
+                    // Special case for DATETRUNC - second parameter can accept any datetime family type. String values should be
+                    // implicitly converted to datetime2. Numeric values are not supported for DATETRUNC
+                    if (index == 1 &&
+                        func.FunctionName.Value.Equals("DATETRUNC", StringComparison.OrdinalIgnoreCase) &&
+                        paramType is SqlDataTypeReference dateTruncParamSqlType &&
+                        dateTruncParamSqlType.SqlDataTypeOption.IsStringType())
+                    {
+                        var dateTimeType = (DataTypeReference)DataTypeHelpers.DateTime2(7);
+                        paramExpr = Convert(context, contextParam, paramExpr, paramType, paramCacheKey, ref dateTimeType, null, null, null, func.Parameters[index], "IMPLICIT", out paramCacheKey);
+                        paramType = dateTimeType;
+                    }
+
+                    // Special case for DATEADD - third parameter can accept any datetime family type. Function is implemented
+                    // to accept datetimeoffset for highest precision, but also needs to accept numeric types which can't be converted
+                    // to datetimeoffset. Convert them to datetime first. Can also accept string values which should be converted
+                    // to datetime
+                    if (index == 2 &&
+                        func.FunctionName.Value.Equals("DATEADD", StringComparison.OrdinalIgnoreCase) &&
+                        paramType is SqlDataTypeReference dateAddParamSqlType &&
+                        (dateAddParamSqlType.SqlDataTypeOption.IsNumeric() || dateAddParamSqlType.SqlDataTypeOption.IsStringType()))
+                    {
+                        var dateTimeType = (DataTypeReference) DataTypeHelpers.DateTime;
+                        paramExpr = Convert(context, contextParam, paramExpr, paramType, paramCacheKey, ref dateTimeType, null, null, null, func.Parameters[index], "IMPLICIT", out paramCacheKey);
+                        paramType = dateTimeType;
+                    }
+
                     return new { Expression = paramExpr, Type = paramType, CacheKey = paramCacheKey, Exception = paramException };
                 })
                 .ToList();
@@ -1081,7 +1119,7 @@ private static MethodInfo GetMethod(ExpressionCompilationContext context, Type t
 
             var method = correctParameterCount[0].Method;
             var parameters = correctParameterCount[0].Parameters;
-            DataTypeReference sourceType = null;
+            var parameterTypes = new Dictionary<string, DataTypeReference>();
             cacheKey = method.Name;
 
             if (correctParameterCount[0].Method.IsGenericMethodDefinition)
@@ -1095,10 +1133,7 @@ private static MethodInfo GetMethod(ExpressionCompilationContext context, Type t
                     for (var i = 0; i < genericArguments.Length; i++)
                     {
                         if (param.ParameterType == genericArguments[i] && genericArgumentValues[i] == null)
-                        {
                             genericArgumentValues[i] = paramTypes[i].ToNetType(out _);
-                            sourceType = paramTypes[i];
-                        }
                     }
                 }
 
@@ -1193,17 +1228,21 @@ private static MethodInfo GetMethod(ExpressionCompilationContext context, Type t
 
                 if (paramType == typeof(DataTypeReference))
                 {
-                    if (parameters[i].GetCustomAttribute<SourceTypeAttribute>() != null)
+                    var sourceType = parameters[i].GetCustomAttribute<SourceTypeAttribute>();
+                    if (sourceType != null)
                     {
-                        cacheKey += $"(TYPE:{sourceType.ToSql()})";
+                        cacheKey += $"(TYPE:{parameterTypes[sourceType.SourceParameter].ToSql()})";
                         if (createExpression)
                         {
                             var paramsWithType = new Expression[paramExpressions.Length + 1];
                             paramExpressions.CopyTo(paramsWithType, 0);
-                            paramsWithType[i] = Expression.Constant(sourceType);
+                            paramsWithType[i] = Expression.Constant(parameterTypes[sourceType.SourceParameter]);
                             paramExpressions = paramsWithType;
                         }
                         hiddenParams++;
+
+                        if (parameters[i].GetCustomAttribute<TargetTypeAttribute>() != null)
+                            sqlType = parameterTypes[sourceType.SourceParameter];
                     }
                     else
                     {
@@ -1242,6 +1281,8 @@ private static MethodInfo GetMethod(ExpressionCompilationContext context, Type t
 
                 if (paramType != typeof(INullable) && !SqlTypeConverter.CanChangeTypeImplicit(paramTypes[i - hiddenParams], paramType.ToSqlType(primaryDataSource)))
                     throw new NotSupportedQueryFragmentException(Sql4CdsError.TypeClash(i < paramOffset ? func : func.Parameters[i - paramOffset], paramTypes[i], paramType.ToSqlType(primaryDataSource)));
+
+                parameterTypes[parameters[i].Name] = paramTypes[i - hiddenParams];
             }
 
             for (var i = parameters.Length; i < paramTypes.Length; i++)
@@ -1262,7 +1303,7 @@ private static MethodInfo GetMethod(ExpressionCompilationContext context, Type t
                     if (arrayType == typeof(INullable))
                         arrayMembers.Add(Expression.Convert(paramExpressions[i], typeof(INullable)));
                     else
-                        arrayMembers.Add(SqlTypeConverter.Convert(paramExpressions[i], arrayType));
+                        arrayMembers.Add(SqlTypeConverter.Convert(paramExpressions[i], contextParam, arrayType));
                 }
 
                 var arrayParam = Expression.NewArrayInit(arrayType, arrayMembers);
@@ -1392,12 +1433,12 @@ private static Expression ToExpression(this FunctionCall func, ExpressionCompila
             for (var i = 0; i < parameters.Length; i++)
             {
                 if (paramValues[i].Type != parameters[i].ParameterType)
-                    paramValues[i] = SqlTypeConverter.Convert(paramValues[i], parameters[i].ParameterType);
+                    paramValues[i] = SqlTypeConverter.Convert(paramValues[i], contextParam, parameters[i].ParameterType);
             }
 
             var expr = (Expression) Expression.Call(method, paramValues);
 
-            if (expr.Type == typeof(object) && parameters.Any(p => p.GetCustomAttribute<TargetTypeAttribute>() != null))
+            if (parameters.Any(p => p.GetCustomAttribute<TargetTypeAttribute>() != null))
                 expr = Expression.Convert(expr, sqlType.ToNetType(out _));
 
             return expr;
@@ -1481,10 +1522,10 @@ private static Expression ToExpression(this InPredicate inPred, ExpressionCompil
                     var convertedExprValue = exprValue;
 
                     if (!exprType.IsSameAs(type))
-                        convertedExprValue = SqlTypeConverter.Convert(convertedExprValue, exprType, type);
+                        convertedExprValue = SqlTypeConverter.Convert(convertedExprValue, contextParam, exprType, type);
 
                     if (!comparisonType.IsSameAs(type))
-                        comparisonValue = SqlTypeConverter.Convert(comparisonValue, comparisonType, type);
+                        comparisonValue = SqlTypeConverter.Convert(comparisonValue, contextParam, comparisonType, type);
 
                     var comparison = inPred.NotDefined ? Expression.NotEqual(convertedExprValue, comparisonValue) : Expression.Equal(convertedExprValue, comparisonValue);
 
@@ -1561,7 +1602,7 @@ private static Expression ToExpression(this BooleanIsNullExpression isNull, Expr
                 cacheKey += " IS NULL";
             }
 
-            value = createExpression ? SqlTypeConverter.Convert(value, typeof(SqlBoolean)) : null;
+            value = createExpression ? SqlTypeConverter.Convert(value, contextParam, typeof(SqlBoolean)) : null;
             sqlType = DataTypeHelpers.Bit;
             return value;
         }
@@ -1587,7 +1628,7 @@ private static Expression ToExpression(this LikePredicate like, ExpressionCompil
                 if (!SqlTypeConverter.CanChangeTypeImplicit(valueType, stringType))
                     throw new NotSupportedQueryFragmentException(Sql4CdsError.TypeClash(like.FirstExpression, valueType, stringType));
 
-                value = createExpression ? SqlTypeConverter.Convert(value, valueType, stringType) : null;
+                value = createExpression ? SqlTypeConverter.Convert(value, contextParam, valueType, stringType) : null;
                 valueType = stringType;
             }
 
@@ -1596,7 +1637,7 @@ private static Expression ToExpression(this LikePredicate like, ExpressionCompil
                 if (!SqlTypeConverter.CanChangeTypeImplicit(patternType, stringType))
                     throw new NotSupportedQueryFragmentException(Sql4CdsError.TypeClash(like.FirstExpression, patternType, stringType));
 
-                pattern = createExpression ? SqlTypeConverter.Convert(pattern, patternType, stringType) : null;
+                pattern = createExpression ? SqlTypeConverter.Convert(pattern, contextParam, patternType, stringType) : null;
                 patternType = stringType;
             }
 
@@ -1605,7 +1646,7 @@ private static Expression ToExpression(this LikePredicate like, ExpressionCompil
                 if (!SqlTypeConverter.CanChangeTypeImplicit(escapeType, stringType))
                     throw new NotSupportedQueryFragmentException(Sql4CdsError.TypeClash(like.FirstExpression, escapeType, stringType));
 
-                escape = createExpression ? SqlTypeConverter.Convert(escape, escapeType, stringType) : null;
+                escape = createExpression ? SqlTypeConverter.Convert(escape, contextParam, escapeType, stringType) : null;
                 escapeType = stringType;
             }
 
@@ -1894,7 +1935,7 @@ private static Expression ToExpression(this SimpleCaseExpression simpleCase, Exp
                 if (elseValue != null)
                 {
                     if (!elseType.IsSameAs(type))
-                        elseValue = SqlTypeConverter.Convert(elseValue, elseType, type);
+                        elseValue = SqlTypeConverter.Convert(elseValue, contextParam, elseType, type);
 
                     result = elseValue;
                 }
@@ -1911,17 +1952,17 @@ private static Expression ToExpression(this SimpleCaseExpression simpleCase, Exp
                     var caseType = caseTypes[i];
 
                     if (!valueType.IsSameAs(caseType))
-                        valueCopy = SqlTypeConverter.Convert(valueCopy, valueType, caseType);
+                        valueCopy = SqlTypeConverter.Convert(valueCopy, contextParam, valueType, caseType);
 
                     if (!whenType.IsSameAs(caseType))
-                        whenValue = SqlTypeConverter.Convert(whenValue, whenType, caseType);
+                        whenValue = SqlTypeConverter.Convert(whenValue, contextParam, whenType, caseType);
 
                     var comparison = Expression.Equal(valueCopy, whenValue);
                     var returnValue = thenClauses[i].Expression;
                     var returnType = thenClauses[i].Type;
 
                     if (!returnType.IsSameAs(type))
-                        returnValue = SqlTypeConverter.Convert(returnValue, returnType, type);
+                        returnValue = SqlTypeConverter.Convert(returnValue, contextParam, returnType, type);
 
                     result = Expression.Condition(Expression.IsTrue(comparison), returnValue, result);
                 }
@@ -1996,7 +2037,7 @@ private static Expression ToExpression(this SearchedCaseExpression searchedCase,
                 if (elseValue != null)
                 {
                     if (!elseType.IsSameAs(type))
-                        elseValue = SqlTypeConverter.Convert(elseValue, elseType, type);
+                        elseValue = SqlTypeConverter.Convert(elseValue, contextParam, elseType, type);
 
                     result = elseValue;
                 }
@@ -2014,10 +2055,10 @@ private static Expression ToExpression(this SearchedCaseExpression searchedCase,
                     var returnValue = thenClauses[i].Expression;
                     var returnType = thenClauses[i].Type;
 
-                    whenValue = SqlTypeConverter.Convert(whenValue, whenType, bitType);
+                    whenValue = SqlTypeConverter.Convert(whenValue, contextParam, whenType, bitType);
                     whenValue = Expression.IsTrue(whenValue);
 
-                    returnValue = SqlTypeConverter.Convert(returnValue, returnType, type);
+                    returnValue = SqlTypeConverter.Convert(returnValue, contextParam, returnType, type);
 
                     result = Expression.Condition(whenValue, returnValue, result);
                 }
@@ -2065,7 +2106,7 @@ private static Expression ToExpression(this BooleanNotExpression not, Expression
             [SqlDataTypeOption.Numeric] = typeof(SqlDecimal),
             [SqlDataTypeOption.NVarChar] = typeof(SqlString),
             [SqlDataTypeOption.Real] = typeof(SqlSingle),
-            [SqlDataTypeOption.SmallDateTime] = typeof(SqlDateTime),
+            [SqlDataTypeOption.SmallDateTime] = typeof(SqlSmallDateTime),
             [SqlDataTypeOption.SmallInt] = typeof(SqlInt16),
             [SqlDataTypeOption.SmallMoney] = typeof(SqlMoney),
             [SqlDataTypeOption.Text] = typeof(SqlString),
@@ -2140,7 +2181,7 @@ public static bool IsType(this DataTypeReference type, SqlDataTypeOption sqlType
             [typeof(SqlGuid)] = DataTypeHelpers.UniqueIdentifier,
             [typeof(SqlEntityReference)] = DataTypeHelpers.EntityReference,
             [typeof(SqlDateTime2)] = DataTypeHelpers.DateTime2(7),
-            [typeof(SqlDateTimeOffset)] = DataTypeHelpers.DateTimeOffset,
+            [typeof(SqlDateTimeOffset)] = DataTypeHelpers.DateTimeOffset(7),
             [typeof(SqlDate)] = DataTypeHelpers.Date,
             [typeof(SqlTime)] = DataTypeHelpers.Time(7),
             [typeof(SqlXml)] = DataTypeHelpers.Xml,
@@ -2173,10 +2214,10 @@ private static Expression ToExpression(this ConvertCall convert, ExpressionCompi
 
             sqlType = convert.DataType;
 
-            return Convert(context, value, valueType, valueCacheKey, ref sqlType, style, styleType, styleCacheKey, convert, "CONVERT", out cacheKey);
+            return Convert(context, contextParam, value, valueType, valueCacheKey, ref sqlType, style, styleType, styleCacheKey, convert, "CONVERT", out cacheKey);
         }
 
-        private static Expression Convert(ExpressionCompilationContext context, Expression value, DataTypeReference valueType, string valueCacheKey, ref DataTypeReference sqlType, Expression style, DataTypeReference styleType, string styleCacheKey, TSqlFragment expr, string cacheKeyRoot, out string cacheKey)
+        private static Expression Convert(ExpressionCompilationContext context, ParameterExpression contextParam, Expression value, DataTypeReference valueType, string valueCacheKey, ref DataTypeReference sqlType, Expression style, DataTypeReference styleType, string styleCacheKey, TSqlFragment expr, string cacheKeyRoot, out string cacheKey)
         {
             if (sqlType is SqlDataTypeReference sqlTargetType &&
                 sqlTargetType.SqlDataTypeOption.IsStringType())
@@ -2205,7 +2246,7 @@ private static Expression Convert(ExpressionCompilationContext context, Expressi
                 cacheKey += ", " + styleCacheKey;
             cacheKey += ")";
 
-            return value == null ? null : SqlTypeConverter.Convert(value, valueType, sqlType, style, styleType, expr);
+            return value == null ? null : SqlTypeConverter.Convert(value, contextParam, valueType, sqlType, style, styleType, expr);
         }
 
         private static Expression ToExpression(this CastCall cast, ExpressionCompilationContext context, ParameterExpression contextParam, ParameterExpression exprParam, bool createExpression, out DataTypeReference sqlType, out string cacheKey)
@@ -2217,7 +2258,7 @@ private static Expression ToExpression(this CastCall cast, ExpressionCompilation
 
             sqlType = cast.DataType;
 
-            return Convert(context, value, valueType, valueCacheKey, ref sqlType, null, null, null, cast, "CAST", out cacheKey);
+            return Convert(context, contextParam, value, valueType, valueCacheKey, ref sqlType, null, null, null, cast, "CAST", out cacheKey);
         }
 
         private static readonly Regex _containsParser = new Regex("^\\S+( OR \\S+)*$", RegexOptions.IgnoreCase | RegexOptions.Compiled);
@@ -2251,7 +2292,7 @@ private static Expression ToExpression(this FullTextPredicate fullText, Expressi
             if (!SqlTypeConverter.CanChangeTypeImplicit(colType, stringType))
                 throw new NotSupportedQueryFragmentException(Sql4CdsError.InvalidColumnForFullTextSearch(fullText.Columns[0]));
 
-            col = createExpression ? SqlTypeConverter.Convert(col, colType, stringType) : null;
+            col = createExpression ? SqlTypeConverter.Convert(col, contextParam, colType, stringType) : null;
             sqlType = DataTypeHelpers.Bit;
 
             if (fullText.Value is StringLiteral lit)
@@ -2268,7 +2309,7 @@ private static Expression ToExpression(this FullTextPredicate fullText, Expressi
             if (!SqlTypeConverter.CanChangeTypeImplicit(valueType, stringType))
                 throw new NotSupportedQueryFragmentException(Sql4CdsError.TypeClash(fullText.Value, valueType, stringType));
 
-            value = createExpression ? SqlTypeConverter.Convert(value, valueType, stringType) : null;
+            value = createExpression ? SqlTypeConverter.Convert(value, contextParam, valueType, stringType) : null;
 
             cacheKey = $"{colCacheKey} CONTAINS {valueCacheKey}";
             return createExpression ? Expr.Call(() => Contains(Expr.Arg<SqlString>(), Expr.Arg<SqlString>()), col, value) : null;
@@ -2710,6 +2751,50 @@ public static BooleanComparisonType TransitiveComparison(this BooleanComparisonT
             }
         }
 
+        /// <summary>
+        /// Returns the equivalent Fetch XML condition operator for this comparison
+        /// </summary>
+        /// <param name="cmp">The comparison type to convert to Fetch XML</param>
+        /// <returns>The equivalent Fetch XML condition operator for this comparison</returns>
+        public static bool TryConvertToFetchXml(this BooleanComparisonType cmp, out @operator op)
+        {
+            switch (cmp)
+            {
+                case BooleanComparisonType.Equals:
+                case BooleanComparisonType.IsNotDistinctFrom:
+                    op = @operator.eq;
+                    break;
+
+                case BooleanComparisonType.GreaterThan:
+                    op = @operator.gt;
+                    break;
+
+                case BooleanComparisonType.GreaterThanOrEqualTo:
+                    op = @operator.ge;
+                    break;
+
+                case BooleanComparisonType.LessThan:
+                    op = @operator.lt;
+                    break;
+
+                case BooleanComparisonType.LessThanOrEqualTo:
+                    op = @operator.le;
+                    break;
+
+                case BooleanComparisonType.NotEqualToBrackets:
+                case BooleanComparisonType.NotEqualToExclamation:
+                case BooleanComparisonType.IsDistinctFrom:
+                    op = @operator.ne;
+                    break;
+
+                default:
+                    op = @operator.eq;
+                    return false;
+            }
+
+            return true;
+        }
+
         private static string GetTypeKey(DataTypeReference type, bool includeStringLength)
         {
             if (type is XmlDataTypeReference)
diff --git a/MarkMpn.Sql4Cds.Engine/ExecutionPlan/FetchXmlScan.cs b/MarkMpn.Sql4Cds.Engine/ExecutionPlan/FetchXmlScan.cs
index ae754431..81360f4e 100644
--- a/MarkMpn.Sql4Cds.Engine/ExecutionPlan/FetchXmlScan.cs
+++ b/MarkMpn.Sql4Cds.Engine/ExecutionPlan/FetchXmlScan.cs
@@ -280,16 +280,17 @@ protected override IEnumerable<Entity> ExecuteInternal(NodeExecutionContext cont
         {
             PagesRetrieved = 0;
 
-            if (!context.DataSources.TryGetValue(DataSource, out var dataSource))
+            if (!context.Session.DataSources.TryGetValue(DataSource, out var dataSource))
                 throw new NotSupportedQueryFragmentException("Missing datasource " + DataSource);
 
             var schema = GetSchema(context);
+            var eec = new ExpressionExecutionContext(context);
 
             ApplyParameterValues(context);
 
             FindEntityNameGroupings(dataSource.Metadata);
 
-            VerifyFilterValueTypes(Entity.name, Entity.Items, dataSource);
+            VerifyFilterValueTypes(Entity.name, Entity.Items, dataSource, eec);
 
             var mainEntity = FetchXml.Items.OfType<FetchEntityType>().Single();
             var name = mainEntity.name;
@@ -454,14 +455,14 @@ protected override IEnumerable<Entity> ExecuteInternal(NodeExecutionContext cont
             }
         }
 
-        private void VerifyFilterValueTypes(string entityName, object[] items, DataSource dataSource)
+        private void VerifyFilterValueTypes(string entityName, object[] items, DataSource dataSource, ExpressionExecutionContext context)
         {
             if (items == null)
                 return;
 
             // Check the value(s) supplied for filter values can be converted to the expected types
             foreach (var filter in items.OfType<filter>())
-                VerifyFilterValueTypes(entityName, filter.Items, dataSource);
+                VerifyFilterValueTypes(entityName, filter.Items, dataSource, context);
             
             foreach (var condition in items.OfType<condition>())
             {
@@ -517,17 +518,17 @@ private void VerifyFilterValueTypes(string entityName, object[] items, DataSourc
                 var conversion = SqlTypeConverter.GetConversion(DataTypeHelpers.NVarChar(Int32.MaxValue, dataSource.DefaultCollation, CollationLabel.CoercibleDefault), attrType);
 
                 if (condition.value != null)
-                    conversion(dataSource.DefaultCollation.ToSqlString(condition.value));
+                    conversion(dataSource.DefaultCollation.ToSqlString(condition.value), context);
 
                 if (condition.Items != null)
                 {
                     foreach (var value in condition.Items)
-                        conversion(dataSource.DefaultCollation.ToSqlString(value.Value));
+                        conversion(dataSource.DefaultCollation.ToSqlString(value.Value), context);
                 }
             }
 
             foreach (var linkEntity in items.OfType<FetchLinkEntityType>())
-                VerifyFilterValueTypes(linkEntity.name, linkEntity.Items, dataSource);
+                VerifyFilterValueTypes(linkEntity.name, linkEntity.Items, dataSource, context);
         }
 
         private void AddPagingFilters(filter filter, IQueryExecutionOptions options)
@@ -1019,7 +1020,7 @@ public override IEnumerable<IExecutionPlanNode> GetSources()
 
         public override INodeSchema GetSchema(NodeCompilationContext context)
         {
-            if (!context.DataSources.TryGetValue(DataSource, out var dataSource))
+            if (!context.Session.DataSources.TryGetValue(DataSource, out var dataSource))
                 throw new NotSupportedQueryFragmentException("Missing datasource " + DataSource);
 
             var fetchXmlString = FetchXmlString;
@@ -1474,7 +1475,7 @@ public override IDataExecutionPlanNodeInternal FoldQuery(NodeCompilationContext
 
             // Move partitionid filter to partitionId parameter
             // https://learn.microsoft.com/en-us/power-apps/developer/data-platform/use-elastic-tables?tabs=sdk#query-rows-of-an-elastic-table
-            var meta = context.DataSources[DataSource].Metadata[Entity.name];
+            var meta = context.Session.DataSources[DataSource].Metadata[Entity.name];
 
             if (meta.DataProviderId == DataProviders.ElasticDataProvider && Entity.Items != null)
             {
@@ -1700,7 +1701,7 @@ private void RemoveIdentitySemiJoinLinkEntities(NodeCompilationContext context)
         {
             // If we've got a semi join link entity that matches to the parent entity by primary key,
             // remove the link entity and move the conditions to the parent entity
-            var dataSource = context.DataSources[DataSource];
+            var dataSource = context.Session.DataSources[DataSource];
             Entity.Items = RemoveIdentitySemiJoinLinkEntities(Entity.name, dataSource.Metadata, Entity.Items);
         }
 
@@ -1981,7 +1982,7 @@ private void MergeNestedFilters(filter filter)
 
         public override void AddRequiredColumns(NodeCompilationContext context, IList<string> requiredColumns)
         {
-            if (!context.DataSources.TryGetValue(DataSource, out var dataSource))
+            if (!context.Session.DataSources.TryGetValue(DataSource, out var dataSource))
                 throw new NotSupportedQueryFragmentException("Missing datasource " + DataSource);
 
             var schema = GetSchema(context);
@@ -2060,7 +2061,7 @@ public override void AddRequiredColumns(NodeCompilationContext context, IList<st
                 Entity.AddItem(new FetchAttributeType { name = metadata.PrimaryIdAttribute });
             }
 
-            if (RequiresCustomPaging(context.DataSources))
+            if (RequiresCustomPaging(context.Session.DataSources))
             {
                 _pagingFields = new List<KeyValuePair<string, string>>();
                 _lastPageValues = new List<INullable>();
@@ -2085,7 +2086,7 @@ public override void AddRequiredColumns(NodeCompilationContext context, IList<st
                 }
             }
 
-            NormalizeAttributes(context.DataSources);
+            NormalizeAttributes(context.Session.DataSources);
             SetDefaultPageSize(context);
         }
 
@@ -2353,10 +2354,10 @@ protected override RowCountEstimate EstimateRowsOutInternal(NodeCompilationConte
                 if (!hasGroups)
                     return RowCountEstimateDefiniteRange.ExactlyOne;
 
-                return EstimateRowsOut(Entity.name, Entity.Items, context.DataSources, 0.4);
+                return EstimateRowsOut(Entity.name, Entity.Items, context.Session.DataSources, 0.4);
             }
 
-            return EstimateRowsOut(Entity.name, Entity.Items, context.DataSources, 1.0);
+            return EstimateRowsOut(Entity.name, Entity.Items, context.Session.DataSources, 1.0);
         }
 
         private bool HasGroups(object[] items)
@@ -2549,6 +2550,95 @@ protected override IEnumerable<string> GetVariablesInternal()
             return FindParameterizedConditions().Keys;
         }
 
+        internal IDataExecutionPlanNodeInternal FoldDmlSource(NodeCompilationContext context, IList<OptimizerHint> hints, string logicalName, string[] requiredColumns, string[] keyAttributes)
+        {
+            if (Entity.name != logicalName || Entity.Items == null)
+                return this;
+
+            // Can't produce any values except the primary key
+            var requiredAttributes = requiredColumns
+                .Select(col => col.SplitMultiPartIdentifier().Last())
+                .ToArray();
+
+            if (requiredAttributes.Except(keyAttributes).Any())
+                return this;
+
+            if (Entity.GetLinkEntities().Any())
+                return this;
+
+            var filters = Entity.Items.OfType<filter>().ToList();
+
+            if (filters.Count != 1)
+                return this;
+
+            if (!filters[0].Items.All(x => x is condition))
+                return this;
+
+            if (filters[0].Items.Cast<condition>().Any(c => c.ValueOf != null))
+                return this;
+
+            var dataSource = context.Session.DataSources[DataSource];
+            var metadata = dataSource.Metadata[logicalName];
+            var conditions = filters[0].Items.Cast<condition>().ToList();
+            var ecc = new ExpressionCompilationContext(context, null, null);
+            var schema = GetSchema(context);
+            var constantScan = new ConstantScanNode
+            {
+                Alias = Alias
+            };
+
+            for (var i = 0; i < requiredColumns.Length; i++)
+                constantScan.Schema[requiredAttributes[i]] = schema.Schema[requiredColumns[i]];
+
+            // We can handle compound keys, but only if they are all ANDed together
+            if (keyAttributes.Length > 1 && filters[0].type == filterType.and)
+            {
+                var values = new Dictionary<string, ScalarExpression>();
+
+                foreach (var keyAttribute in keyAttributes)
+                {
+                    var condition = conditions.FirstOrDefault(c => c.attribute == keyAttribute);
+                    if (condition == null)
+                        return this;
+
+                    if (condition.@operator != @operator.eq)
+                        return this;
+
+                    var attribute = metadata.Attributes.Single(a => a.LogicalName == condition.attribute);
+                    values[condition.attribute] = attribute.GetDmlValue(condition.value, condition.IsVariable, ecc, dataSource);
+                }
+
+                constantScan.Values.Add(values);
+                return constantScan;
+            }
+
+            // We can also handle multiple values for a single key being ORed together
+            else if (keyAttributes.Length == 1 &&
+                conditions.All(c => c.attribute == metadata.PrimaryIdAttribute) &&
+                conditions.All(c => c.@operator == @operator.eq || c.@operator == @operator.@in) &&
+                (conditions.Count == 1 || filters[0].type == filterType.or))
+            {
+                foreach (var condition in conditions)
+                {
+                    var attribute = metadata.Attributes.Single(a => a.LogicalName == condition.attribute);
+
+                    if (condition.@operator == @operator.eq)
+                    {
+                        constantScan.Values.Add(new Dictionary<string, ScalarExpression> { [condition.attribute] = attribute.GetDmlValue(condition.value, condition.IsVariable, ecc, dataSource) });
+                    }
+                    else if (condition.@operator == @operator.@in)
+                    {
+                        foreach (var value in condition.Items)
+                            constantScan.Values.Add(new Dictionary<string, ScalarExpression> { [condition.attribute] = attribute.GetDmlValue(value.Value, value.IsVariable, ecc, dataSource) });
+                    }
+                }
+
+                return constantScan;
+            }
+
+            return this;
+        }
+
         public override string ToString()
         {
             return "FetchXML Query";
diff --git a/MarkMpn.Sql4Cds.Engine/ExecutionPlan/FilterNode.cs b/MarkMpn.Sql4Cds.Engine/ExecutionPlan/FilterNode.cs
index 5ba5a272..813b840b 100644
--- a/MarkMpn.Sql4Cds.Engine/ExecutionPlan/FilterNode.cs
+++ b/MarkMpn.Sql4Cds.Engine/ExecutionPlan/FilterNode.cs
@@ -1081,7 +1081,7 @@ private bool FoldInExistsToFetchXml(NodeCompilationContext context, IList<Optimi
                     break;
 
                 // Only supported on regular database tables
-                var leftMeta = context.DataSources[leftFetch.DataSource].Metadata[leftFetch.Entity.name];
+                var leftMeta = context.Session.DataSources[leftFetch.DataSource].Metadata[leftFetch.Entity.name];
                 if (leftMeta.DataProviderId != null)
                     break;
 
@@ -1135,8 +1135,8 @@ private bool FoldInExistsToFetchXml(NodeCompilationContext context, IList<Optimi
                     if (nullFilterRemovable &&
                         nullFilter.IsNot &&
                         leftFetch.Entity.name == rightFetch.Entity.name &&
-                        merge.LeftAttribute.GetColumnName() == leftFetch.Alias + "." + context.DataSources[leftFetch.DataSource].Metadata[leftFetch.Entity.name].PrimaryIdAttribute &&
-                        merge.RightAttribute.GetColumnName() == rightFetch.Alias + "." + context.DataSources[rightFetch.DataSource].Metadata[rightFetch.Entity.name].PrimaryIdAttribute &&
+                        merge.LeftAttribute.GetColumnName() == leftFetch.Alias + "." + context.Session.DataSources[leftFetch.DataSource].Metadata[leftFetch.Entity.name].PrimaryIdAttribute &&
+                        merge.RightAttribute.GetColumnName() == rightFetch.Alias + "." + context.Session.DataSources[rightFetch.DataSource].Metadata[rightFetch.Entity.name].PrimaryIdAttribute &&
                         !leftFetch.Entity.GetLinkEntities().Select(l => l.alias).Intersect(rightFetch.Entity.GetLinkEntities().Select(l => l.alias), StringComparer.OrdinalIgnoreCase).Any() &&
                         (leftFetch.FetchXml.top == null || rightFetch.FetchXml.top == null))
                     {
@@ -1210,7 +1210,7 @@ private bool FoldInExistsToFetchXml(NodeCompilationContext context, IList<Optimi
                     // We need to use an "in" join type - check that's supported
                     else if (nullFilterRemovable &&
                         nullFilter.IsNot &&
-                        context.DataSources[rightFetch.DataSource].JoinOperatorsAvailable.Contains(JoinOperator.In) &&
+                        context.Session.DataSources[rightFetch.DataSource].JoinOperatorsAvailable.Contains(JoinOperator.In) &&
                         rightFetch.FetchXml.top == null)
                     {
                         // Remove the filter and replace with an "in" link-entity
@@ -1232,7 +1232,7 @@ private bool FoldInExistsToFetchXml(NodeCompilationContext context, IList<Optimi
                     // We can use an "any" join type - check that's supported
                     else if (!nullFilterRemovable &&
                         nullFilter.IsNot &&
-                        context.DataSources[rightFetch.DataSource].JoinOperatorsAvailable.Contains(JoinOperator.Any) &&
+                        context.Session.DataSources[rightFetch.DataSource].JoinOperatorsAvailable.Contains(JoinOperator.Any) &&
                         rightFetch.FetchXml.top == null)
                     {
                         if (subqueryConditions.ContainsKey(nullFilter))
@@ -1270,7 +1270,7 @@ private bool FoldInExistsToFetchXml(NodeCompilationContext context, IList<Optimi
                             break;
 
                         // Replace the filter on the defined value name with a filter on the primary key column
-                        nullFilter.Expression = (rightFetch.Alias + "." + context.DataSources[rightFetch.DataSource].Metadata[rightFetch.Entity.name].PrimaryIdAttribute).ToColumnReference();
+                        nullFilter.Expression = (rightFetch.Alias + "." + context.Session.DataSources[rightFetch.DataSource].Metadata[rightFetch.Entity.name].PrimaryIdAttribute).ToColumnReference();
 
                         rightFetch.RemoveSorts();
 
@@ -1346,7 +1346,7 @@ private bool FoldInExistsToFetchXml(NodeCompilationContext context, IList<Optimi
                     
                     leftAlias = outerReferenceParts[0];
 
-                    if (context.DataSources[rightFetch.DataSource].JoinOperatorsAvailable.Contains(JoinOperator.Exists) &&
+                    if (context.Session.DataSources[rightFetch.DataSource].JoinOperatorsAvailable.Contains(JoinOperator.Exists) &&
                         notNullFilter.IsNot &&
                         notNullFilterRemovable)
                     {
@@ -1364,8 +1364,8 @@ private bool FoldInExistsToFetchXml(NodeCompilationContext context, IList<Optimi
                         };
                         semiJoin = true;
                     }
-                    else if (context.DataSources[rightFetch.DataSource].JoinOperatorsAvailable.Contains(JoinOperator.Any) && notNullFilter.IsNot ||
-                        context.DataSources[rightFetch.DataSource].JoinOperatorsAvailable.Contains(JoinOperator.NotAny) && !notNullFilter.IsNot)
+                    else if (context.Session.DataSources[rightFetch.DataSource].JoinOperatorsAvailable.Contains(JoinOperator.Any) && notNullFilter.IsNot ||
+                        context.Session.DataSources[rightFetch.DataSource].JoinOperatorsAvailable.Contains(JoinOperator.NotAny) && !notNullFilter.IsNot)
                     {
                         if (subqueryConditions.ContainsKey(notNullFilter))
                             break; // We've already processed this subquery
@@ -1515,7 +1515,7 @@ private bool FoldFiltersToDataSources(NodeCompilationContext context, IList<Opti
 
                 if (source is FetchXmlScan fetchXml && !fetchXml.FetchXml.aggregate)
                 {
-                    if (!foldableContext.DataSources.TryGetValue(fetchXml.DataSource, out var dataSource))
+                    if (!foldableContext.Session.DataSources.TryGetValue(fetchXml.DataSource, out var dataSource))
                         throw new NotSupportedQueryFragmentException("Missing datasource " + fetchXml.DataSource);
 
                     // If the criteria are ANDed, see if any of the individual conditions can be translated to FetchXML
@@ -2033,7 +2033,7 @@ protected bool TranslateMetadataCriteria(NodeCompilationContext context, Boolean
             keyFilter = null;
 
             var expressionCompilationContext = new ExpressionCompilationContext(context, null, null);
-            var expressionExecutionContext = new ExpressionExecutionContext(new NodeExecutionContext(context.DataSources, context.Options, context.ParameterTypes, null, null));
+            var expressionExecutionContext = new ExpressionExecutionContext(new NodeExecutionContext(context, null));
 
             if (criteria is BooleanBinaryExpression binary)
             {
diff --git a/MarkMpn.Sql4Cds.Engine/ExecutionPlan/FoldableJoinNode.cs b/MarkMpn.Sql4Cds.Engine/ExecutionPlan/FoldableJoinNode.cs
index 843af188..32a18088 100644
--- a/MarkMpn.Sql4Cds.Engine/ExecutionPlan/FoldableJoinNode.cs
+++ b/MarkMpn.Sql4Cds.Engine/ExecutionPlan/FoldableJoinNode.cs
@@ -433,7 +433,7 @@ private bool FoldFetchXmlJoin(NodeCompilationContext context, IList<OptimizerHin
                 return false;
 
             // If the entities are from different virtual entity data providers it's probably not going to work
-            if (!context.DataSources.TryGetValue(leftFetch.DataSource, out var dataSource))
+            if (!context.Session.DataSources.TryGetValue(leftFetch.DataSource, out var dataSource))
                 throw new NotSupportedQueryFragmentException("Missing datasource " + leftFetch.DataSource);
 
             if (dataSource.Metadata[leftFetch.Entity.name].DataProviderId != dataSource.Metadata[rightFetch.Entity.name].DataProviderId)
@@ -534,7 +534,7 @@ private bool FoldFetchXmlJoin(NodeCompilationContext context, IList<OptimizerHin
                 folded = new FilterNode { Filter = additionalCriteria, Source = leftFetch }.FoldQuery(context, hints);
 
             // We might have previously folded a sort to the FetchXML that is no longer valid as we require custom paging
-            if (leftFetch.RequiresCustomPaging(context.DataSources))
+            if (leftFetch.RequiresCustomPaging(context.Session.DataSources))
                 leftFetch.RemoveSorts();
 
             // We might have previously folded a not-null condition that is no longer required as it is implicit in the join
diff --git a/MarkMpn.Sql4Cds.Engine/ExecutionPlan/GlobalOptionSetQueryNode.cs b/MarkMpn.Sql4Cds.Engine/ExecutionPlan/GlobalOptionSetQueryNode.cs
index 31b6ea4f..5252ebd7 100644
--- a/MarkMpn.Sql4Cds.Engine/ExecutionPlan/GlobalOptionSetQueryNode.cs
+++ b/MarkMpn.Sql4Cds.Engine/ExecutionPlan/GlobalOptionSetQueryNode.cs
@@ -17,7 +17,7 @@ class GlobalOptionSetQueryNode : BaseDataNode
         class OptionSetProperty
         {
             public string Name { get; set; }
-            public IDictionary<Type, Func<object, object>> Accessors { get; set; }
+            public IDictionary<Type, Func<object, ExpressionExecutionContext, object>> Accessors { get; set; }
             public DataTypeReference SqlType { get; set; }
             public Type NetType { get; set; }
             public IComparable[] DataMemberOrder { get; set; }
@@ -157,10 +157,11 @@ public override IEnumerable<IExecutionPlanNode> GetSources()
 
         protected override IEnumerable<Entity> ExecuteInternal(NodeExecutionContext context)
         {
-            if (!context.DataSources.TryGetValue(DataSource, out var dataSource))
+            if (!context.Session.DataSources.TryGetValue(DataSource, out var dataSource))
                 throw new NotSupportedQueryFragmentException("Missing datasource " + DataSource);
 
             var resp = (RetrieveAllOptionSetsResponse)dataSource.Connection.Execute(new RetrieveAllOptionSetsRequest());
+            var eec = new ExpressionExecutionContext(context);
 
             foreach (var optionset in resp.OptionSetMetadata)
             {
@@ -174,7 +175,7 @@ protected override IEnumerable<Entity> ExecuteInternal(NodeExecutionContext cont
                         continue;
                     }
 
-                    converted[col.Key] = optionsetProp(optionset);
+                    converted[col.Key] = optionsetProp(optionset, eec);
                 }
 
                 yield return converted;
diff --git a/MarkMpn.Sql4Cds.Engine/ExecutionPlan/HashMatchAggregateNode.cs b/MarkMpn.Sql4Cds.Engine/ExecutionPlan/HashMatchAggregateNode.cs
index 066b52e5..16349329 100644
--- a/MarkMpn.Sql4Cds.Engine/ExecutionPlan/HashMatchAggregateNode.cs
+++ b/MarkMpn.Sql4Cds.Engine/ExecutionPlan/HashMatchAggregateNode.cs
@@ -58,7 +58,7 @@ protected override IEnumerable<Entity> ExecuteInternal(NodeExecutionContext cont
                 executionContext.Entity = entity;
 
                 foreach (var func in values.Values)
-                    func.AggregateFunction.NextRecord(func.State);
+                    func.AggregateFunction.NextRecord(func.State, executionContext);
             }
 
             foreach (var group in groups)
@@ -98,7 +98,7 @@ Source is FetchXmlScan fetch &&
                 GroupBy.Count == 0 &&
                 Aggregates.Count == 1 &&
                 Aggregates.Single().Value.AggregateType == AggregateType.CountStar &&
-                context.DataSources[fetch.DataSource].Metadata[fetch.Entity.name].DataProviderId == null && // RetrieveTotalRecordCountRequest is not valid for virtual entities
+                context.Session.DataSources[fetch.DataSource].Metadata[fetch.Entity.name].DataProviderId == null && // RetrieveTotalRecordCountRequest is not valid for virtual entities
                 fetch.FetchXml.DataSource == null) // RetrieveTotalRecordCountRequest is not valid for archive data
             {
                 var count = new RetrieveTotalRecordCountNode { DataSource = fetch.DataSource, EntityName = fetch.Entity.name };
@@ -269,7 +269,7 @@ Source is FetchXmlScan fetch &&
                     }
                 }
 
-                var metadata = context.DataSources[fetchXml.DataSource].Metadata;
+                var metadata = context.Session.DataSources[fetchXml.DataSource].Metadata;
 
                 // Aggregates are not supported on archive data
                 if (fetchXml.FetchXml.DataSource == "retained")
diff --git a/MarkMpn.Sql4Cds.Engine/ExecutionPlan/IndexSpoolNode.cs b/MarkMpn.Sql4Cds.Engine/ExecutionPlan/IndexSpoolNode.cs
index 2f451740..dc423336 100644
--- a/MarkMpn.Sql4Cds.Engine/ExecutionPlan/IndexSpoolNode.cs
+++ b/MarkMpn.Sql4Cds.Engine/ExecutionPlan/IndexSpoolNode.cs
@@ -18,8 +18,8 @@ namespace MarkMpn.Sql4Cds.Engine.ExecutionPlan
     class IndexSpoolNode : BaseDataNode, ISingleSourceExecutionPlanNode, ISpoolProducerNode
     {
         private IDictionary<INullable, List<Entity>> _hashTable;
-        private Func<INullable, INullable> _keySelector;
-        private Func<INullable, INullable> _seekSelector;
+        private Func<INullable, ExpressionExecutionContext, INullable> _keySelector;
+        private Func<INullable, ExpressionExecutionContext, INullable> _seekSelector;
         private Stack<Entity> _stack;
 
         [Browsable(false)]
@@ -219,7 +219,7 @@ private IDataExecutionPlanNodeInternal FoldCTEToFetchXml(NodeCompilationContext
                     return this;
             }
 
-            var metadata = context.DataSources[anchorFetchXml.DataSource].Metadata[anchorFetchXml.Entity.name];
+            var metadata = context.Session.DataSources[anchorFetchXml.DataSource].Metadata[anchorFetchXml.Entity.name];
             var hierarchicalRelationship = metadata.OneToManyRelationships.SingleOrDefault(r => r.IsHierarchical == true);
 
             if (hierarchicalRelationship == null ||
@@ -411,15 +411,22 @@ protected override IEnumerable<Entity> ExecuteInternal(NodeExecutionContext cont
             if (WithStack)
                 return ExecuteInternalWithStack(context);
 
+            var eec = new ExpressionExecutionContext(context);
+
             // Build an internal hash table of the source indexed by the key column
             if (_hashTable == null)
             {
                 _hashTable = Source.Execute(context)
-                    .GroupBy(e => _keySelector((INullable)e[KeyColumn]))
+                    .GroupBy(e =>
+                    {
+                        eec.Entity = e;
+                        return _keySelector((INullable)e[KeyColumn], eec);
+                    })
                     .ToDictionary(g => g.Key, g => g.ToList());
             }
 
-            var keyValue = _seekSelector((INullable)context.ParameterValues[SeekValue]);
+            eec.Entity = null;
+            var keyValue = _seekSelector((INullable)context.ParameterValues[SeekValue], eec);
 
             if (!_hashTable.TryGetValue(keyValue, out var matches))
                 return Array.Empty<Entity>();
diff --git a/MarkMpn.Sql4Cds.Engine/ExecutionPlan/InsertNode.cs b/MarkMpn.Sql4Cds.Engine/ExecutionPlan/InsertNode.cs
index 491d19e2..89e70332 100644
--- a/MarkMpn.Sql4Cds.Engine/ExecutionPlan/InsertNode.cs
+++ b/MarkMpn.Sql4Cds.Engine/ExecutionPlan/InsertNode.cs
@@ -85,7 +85,7 @@ private bool GetIgnoreDuplicateKey(NodeCompilationContext context, IList<Optimiz
             if (!ignoreDupKey && LogicalName == "listmember")
             {
                 ignoreDupKey = true;
-                context.Log(new Sql4CdsError(10, LineNumber, 0, null, context.DataSources[DataSource].Name, 0, "Duplicate entries will be silently ignored for listmember inserts"));
+                context.Log(new Sql4CdsError(10, LineNumber, 0, null, context.Session.DataSources[DataSource].Name, 0, "Duplicate entries will be silently ignored for listmember inserts"));
             }
 
             return ignoreDupKey;
@@ -110,14 +110,15 @@ public override void Execute(NodeExecutionContext context, out int recordsAffect
 
             try
             {
-                if (!context.DataSources.TryGetValue(DataSource, out var dataSource))
+                if (!context.Session.DataSources.TryGetValue(DataSource, out var dataSource))
                     throw new QueryExecutionException("Missing datasource " + DataSource);
 
                 List<Entity> entities;
                 EntityMetadata meta;
                 Dictionary<string, AttributeMetadata> attributes;
-                Dictionary<string, Func<Entity, object>> attributeAccessors;
-                Func<Entity, object> primaryIdAccessor;
+                Dictionary<string, Func<ExpressionExecutionContext, object>> attributeAccessors;
+                Func<ExpressionExecutionContext, object> primaryIdAccessor;
+                var eec = new ExpressionExecutionContext(context);
 
                 using (_timer.Run())
                 {
@@ -146,7 +147,11 @@ public override void Execute(NodeExecutionContext context, out int recordsAffect
                         context.Options,
                         entities,
                         meta,
-                        entity => CreateInsertRequest(meta, entity, attributeAccessors, primaryIdAccessor, attributes),
+                        entity =>
+                        {
+                            eec.Entity = entity;
+                            return CreateInsertRequest(meta, eec, attributeAccessors, primaryIdAccessor, attributes);
+                        },
                         new OperationNames
                         {
                             InProgressUppercase = "Inserting",
@@ -173,13 +178,13 @@ public override void Execute(NodeExecutionContext context, out int recordsAffect
             }
         }
 
-        private OrganizationRequest CreateInsertRequest(EntityMetadata meta, Entity entity, Dictionary<string,Func<Entity,object>> attributeAccessors, Func<Entity,object> primaryIdAccessor, Dictionary<string,AttributeMetadata> attributes)
+        private OrganizationRequest CreateInsertRequest(EntityMetadata meta, ExpressionExecutionContext context, Dictionary<string,Func<ExpressionExecutionContext,object>> attributeAccessors, Func<ExpressionExecutionContext,object> primaryIdAccessor, Dictionary<string,AttributeMetadata> attributes)
         {
             // Special cases for intersect entities
             if (LogicalName == "listmember")
             {
-                var listId = GetNotNull<Guid>("listid", entity, attributeAccessors);
-                var entityId = GetNotNull<Guid>("entityid", entity, attributeAccessors);
+                var listId = GetNotNull<Guid>("listid", context, attributeAccessors);
+                var entityId = GetNotNull<Guid>("entityid", context, attributeAccessors);
 
                 return new AddMemberListRequest
                 {
@@ -194,8 +199,8 @@ private OrganizationRequest CreateInsertRequest(EntityMetadata meta, Entity enti
                 // the relationship that this is the intersect entity for
                 var relationship = meta.ManyToManyRelationships.Single();
 
-                var e1 = GetNotNull<Guid>(relationship.Entity1IntersectAttribute, entity, attributeAccessors);
-                var e2 = GetNotNull<Guid>(relationship.Entity2IntersectAttribute, entity, attributeAccessors);
+                var e1 = GetNotNull<Guid>(relationship.Entity1IntersectAttribute, context, attributeAccessors);
+                var e2 = GetNotNull<Guid>(relationship.Entity2IntersectAttribute, context, attributeAccessors);
 
                 return new AssociateRequest
                 {
@@ -208,9 +213,9 @@ private OrganizationRequest CreateInsertRequest(EntityMetadata meta, Entity enti
             if (LogicalName == "principalobjectaccess")
             {
                 // Insert into principalobjectaccess is equivalent to a share
-                var objectId = GetNotNull<EntityReference>("objectid", entity, attributeAccessors);
-                var principalId = GetNotNull<EntityReference>("principalid", entity, attributeAccessors);
-                var accessRightsMask = GetNotNull<int>("accessrightsmask", entity, attributeAccessors);
+                var objectId = GetNotNull<EntityReference>("objectid", context, attributeAccessors);
+                var principalId = GetNotNull<EntityReference>("principalid", context, attributeAccessors);
+                var accessRightsMask = GetNotNull<int>("accessrightsmask", context, attributeAccessors);
 
                 return new GrantAccessRequest
                 {
@@ -226,7 +231,7 @@ private OrganizationRequest CreateInsertRequest(EntityMetadata meta, Entity enti
             var insert = new Entity(LogicalName);
 
             if (primaryIdAccessor != null)
-                insert.Id = (Guid) primaryIdAccessor(entity);
+                insert.Id = (Guid) primaryIdAccessor(context);
 
             foreach (var attributeAccessor in attributeAccessors)
             {
@@ -238,7 +243,7 @@ private OrganizationRequest CreateInsertRequest(EntityMetadata meta, Entity enti
                 if (!String.IsNullOrEmpty(attr.AttributeOf))
                     continue;
 
-                var value = attributeAccessor.Value(entity);
+                var value = attributeAccessor.Value(context);
 
                 insert[attr.LogicalName] = value;
             }
@@ -246,9 +251,9 @@ private OrganizationRequest CreateInsertRequest(EntityMetadata meta, Entity enti
             return new CreateRequest { Target = insert };
         }
 
-        private T GetNotNull<T>(string attribute, Entity entity, Dictionary<string, Func<Entity, object>> attributeAccessors)
+        private T GetNotNull<T>(string attribute, ExpressionExecutionContext context, Dictionary<string, Func<ExpressionExecutionContext, object>> attributeAccessors)
         {
-            var value = attributeAccessors[attribute](entity);
+            var value = attributeAccessors[attribute](context);
 
             if (value == null)
                 throw new QueryExecutionException(Sql4CdsError.NotNullInsert(new Identifier { Value = attribute }, new Identifier { Value = LogicalName }, "Insert"));
@@ -285,7 +290,7 @@ protected override bool FilterErrors(NodeExecutionContext context, OrganizationR
                             logMessage += $". The duplicate values were ({create.Target.Id})";
                     }
 
-                    context.Log(new Sql4CdsError(10, LineNumber, 0, null, context.DataSources[DataSource].Name, 0, logMessage));
+                    context.Log(new Sql4CdsError(10, LineNumber, 0, null, context.Session.DataSources[DataSource].Name, 0, logMessage));
                     return false;
                 }
             }
diff --git a/MarkMpn.Sql4Cds.Engine/ExecutionPlan/MetadataQueryNode.cs b/MarkMpn.Sql4Cds.Engine/ExecutionPlan/MetadataQueryNode.cs
index c399ce66..c9600e75 100644
--- a/MarkMpn.Sql4Cds.Engine/ExecutionPlan/MetadataQueryNode.cs
+++ b/MarkMpn.Sql4Cds.Engine/ExecutionPlan/MetadataQueryNode.cs
@@ -26,7 +26,7 @@ class MetadataProperty
         {
             public string SqlName { get; set; }
             public string PropertyName { get; set; }
-            public Func<object,object> Accessor { get; set; }
+            public Func<object,ExpressionExecutionContext,object> Accessor { get; set; }
             public DataTypeReference SqlType { get; set; }
             public Type Type { get; set; }
             public IComparable[] DataMemberOrder { get; set; }
@@ -36,7 +36,7 @@ class AttributeProperty
         {
             public string SqlName { get; set; }
             public string PropertyName { get; set; }
-            public IDictionary<Type, Func<object,object>> Accessors { get; set; }
+            public IDictionary<Type, Func<object,ExpressionExecutionContext,object>> Accessors { get; set; }
             public DataTypeReference SqlType { get; set; }
             public Type Type { get; set; }
             public bool IsNullable { get; set; }
@@ -552,7 +552,7 @@ private CompiledExpression CompileExpression(ScalarExpression expression, Expres
             var targetNetType = targetSqlType.ToNetType(out _);
             var netConverter = SqlTypeConverter.GetConversion(targetNetType, targetValueType);
 
-            return new CompiledExpression(expression, context => netConverter(sqlConverter((INullable)expr(context))));
+            return new CompiledExpression(expression, context => netConverter(sqlConverter((INullable)expr(context), context), context));
         }
 
         public override INodeSchema GetSchema(NodeCompilationContext context)
@@ -843,10 +843,11 @@ internal static DataTypeReference GetPropertyType(Type propType)
             return SqlTypeConverter.NetToSqlType(propType).ToSqlType(null);
         }
 
-        internal static Func<object,object> GetPropertyAccessor(PropertyInfo prop, Type targetType)
+        internal static Func<object,ExpressionExecutionContext,object> GetPropertyAccessor(PropertyInfo prop, Type targetType)
         {
             var rawParam = Expression.Parameter(typeof(object));
-            var param = SqlTypeConverter.Convert(rawParam, prop.DeclaringType);
+            var contextParam = Expression.Parameter(typeof(ExpressionExecutionContext));
+            var param = SqlTypeConverter.Convert(rawParam, contextParam, prop.DeclaringType);
             var value = (Expression)Expression.Property(param, prop);
 
             // Extract base value from complex types
@@ -869,13 +870,13 @@ internal static Func<object,object> GetPropertyAccessor(PropertyInfo prop, Type
                 value = Expression.Property(value, nameof(Label.UserLocalizedLabel));
 
             if (value.Type == typeof(LocalizedLabel))
-                value = Expression.Condition(Expression.Equal(value, Expression.Constant(null)), SqlTypeConverter.Convert(Expression.Constant(null), typeof(string)), Expression.Property(value, nameof(LocalizedLabel.Label)));
+                value = Expression.Condition(Expression.Equal(value, Expression.Constant(null)), Expression.Constant(null, typeof(string)), Expression.Property(value, nameof(LocalizedLabel.Label)));
 
             if (value.Type.IsEnum)
                 value = Expression.Call(value, nameof(Enum.ToString), Array.Empty<Type>());
 
             if (typeof(MetadataBase).IsAssignableFrom(value.Type))
-                value = Expression.Condition(Expression.Equal(value, Expression.Constant(null)), SqlTypeConverter.Convert(Expression.Constant(null), typeof(Guid?)), Expression.Property(value, nameof(MetadataBase.MetadataId)));
+                value = Expression.Condition(Expression.Equal(value, Expression.Constant(null)), Expression.Constant(null, typeof(Guid?)), Expression.Property(value, nameof(MetadataBase.MetadataId)));
 
             var directConversionType = SqlTypeConverter.NetToSqlType(value.Type);
 
@@ -887,10 +888,10 @@ internal static Func<object,object> GetPropertyAccessor(PropertyInfo prop, Type
             if (value.Type == typeof(string) && directConversionType == typeof(SqlString) && targetType == typeof(SqlString))
                 converted = Expr.Call(() => ApplyCollation(Expr.Arg<string>()), value);
             else
-                converted = SqlTypeConverter.Convert(value, directConversionType);
+                converted = SqlTypeConverter.Convert(value, contextParam, directConversionType);
 
             if (targetType != directConversionType)
-                converted = SqlTypeConverter.Convert(converted, targetType);
+                converted = SqlTypeConverter.Convert(converted, contextParam, targetType);
 
             // Return null literal if final value is null
             if (!value.Type.IsValueType)
@@ -904,7 +905,7 @@ internal static Func<object,object> GetPropertyAccessor(PropertyInfo prop, Type
 
             // Compile the function
             value = Expr.Box(value);
-            var func = (Func<object,object>) Expression.Lambda(value, rawParam).Compile();
+            var func = (Func<object,ExpressionExecutionContext,object>) Expression.Lambda(value, rawParam, contextParam).Compile();
             return func;
         }
 
@@ -1000,7 +1001,7 @@ protected override IEnumerable<Entity> ExecuteInternal(NodeExecutionContext cont
                     query.Properties.PropertyNames.Add(nameof(EntityMetadata.Keys));
             }
 
-            if (!context.DataSources.TryGetValue(DataSource, out var dataSource))
+            if (!context.Session.DataSources.TryGetValue(DataSource, out var dataSource))
                 throw new NotSupportedQueryFragmentException("Missing datasource " + DataSource);
 
             var resp = (RetrieveMetadataChangesResponse)dataSource.Connection.Execute(new RetrieveMetadataChangesRequest { Query = query });
@@ -1009,6 +1010,7 @@ protected override IEnumerable<Entity> ExecuteInternal(NodeExecutionContext cont
             var oneToManyRelationshipProps = typeof(OneToManyRelationshipMetadata).GetProperties().ToDictionary(p => p.Name);
             var manyToManyRelationshipProps = typeof(ManyToManyRelationshipMetadata).GetProperties().ToDictionary(p => p.Name);
             var keyProps = typeof(EntityKeyMetadata).GetProperties().ToDictionary(p => p.Name);
+            var eec = new ExpressionExecutionContext(context);
 
             var results = resp.EntityMetadata.Select(e => new { Entity = e, Attribute = (AttributeMetadata)null, Relationship = (RelationshipMetadataBase)null, Key = (EntityKeyMetadata)null });
 
@@ -1037,7 +1039,7 @@ protected override IEnumerable<Entity> ExecuteInternal(NodeExecutionContext cont
                     converted.Id = result.Entity.MetadataId ?? Guid.Empty;
 
                     foreach (var prop in _entityCols)
-                        converted[prop.Key] = prop.Value.Accessor(result.Entity);
+                        converted[prop.Key] = prop.Value.Accessor(result.Entity, eec);
                 }
 
                 if (MetadataSource.HasFlag(MetadataSource.Attribute))
@@ -1053,7 +1055,7 @@ protected override IEnumerable<Entity> ExecuteInternal(NodeExecutionContext cont
                             continue;
                         }
 
-                        converted[prop.Key] = accessor(result.Attribute);
+                        converted[prop.Key] = accessor(result.Attribute, eec);
                     }
                 }
 
@@ -1063,7 +1065,7 @@ protected override IEnumerable<Entity> ExecuteInternal(NodeExecutionContext cont
                     converted.Id = result.Relationship.MetadataId ?? Guid.Empty;
 
                     foreach (var prop in _oneToManyRelationshipCols)
-                        converted[prop.Key] = prop.Value.Accessor(result.Relationship);
+                        converted[prop.Key] = prop.Value.Accessor(result.Relationship, eec);
                 }
 
                 if (MetadataSource.HasFlag(MetadataSource.ManyToOneRelationship))
@@ -1072,7 +1074,7 @@ protected override IEnumerable<Entity> ExecuteInternal(NodeExecutionContext cont
                     converted.Id = result.Relationship.MetadataId ?? Guid.Empty;
 
                     foreach (var prop in _manyToOneRelationshipCols)
-                        converted[prop.Key] = prop.Value.Accessor(result.Relationship);
+                        converted[prop.Key] = prop.Value.Accessor(result.Relationship, eec);
                 }
 
                 if (MetadataSource.HasFlag(MetadataSource.ManyToManyRelationship))
@@ -1081,7 +1083,7 @@ protected override IEnumerable<Entity> ExecuteInternal(NodeExecutionContext cont
                     converted.Id = result.Relationship.MetadataId ?? Guid.Empty;
 
                     foreach (var prop in _manyToManyRelationshipCols)
-                        converted[prop.Key] = prop.Value.Accessor(result.Relationship);
+                        converted[prop.Key] = prop.Value.Accessor(result.Relationship, eec);
                 }
 
                 if (MetadataSource.HasFlag(MetadataSource.Key))
@@ -1090,7 +1092,7 @@ protected override IEnumerable<Entity> ExecuteInternal(NodeExecutionContext cont
                     converted.Id = result.Key.MetadataId ?? Guid.Empty;
 
                     foreach (var prop in _keyCols)
-                        converted[prop.Key] = prop.Value.Accessor(result.Key);
+                        converted[prop.Key] = prop.Value.Accessor(result.Key, eec);
                 }
 
                 foreach (var attr in converted.Attributes.ToList())
diff --git a/MarkMpn.Sql4Cds.Engine/ExecutionPlan/NestedLoopNode.cs b/MarkMpn.Sql4Cds.Engine/ExecutionPlan/NestedLoopNode.cs
index 91436897..3273e85b 100644
--- a/MarkMpn.Sql4Cds.Engine/ExecutionPlan/NestedLoopNode.cs
+++ b/MarkMpn.Sql4Cds.Engine/ExecutionPlan/NestedLoopNode.cs
@@ -64,7 +64,7 @@ protected override IEnumerable<Entity> ExecuteInternal(NodeExecutionContext cont
                             innerParameterTypes[kvp.Value] = leftSchema.Schema[kvp.Key].Type;
                     }
 
-                    rightCompilationContext = new NodeCompilationContext(context.DataSources, context.Options, innerParameterTypes, context.Log);
+                    rightCompilationContext = new NodeCompilationContext(context.Session, context.Options, innerParameterTypes, context.Log);
                 }
 
                 var innerParameters = context.ParameterValues;
@@ -85,7 +85,7 @@ protected override IEnumerable<Entity> ExecuteInternal(NodeExecutionContext cont
 
                 var hasRight = false;
 
-                foreach (var right in RightSource.Execute(new NodeExecutionContext(context.DataSources, context.Options, innerParameterTypes, innerParameters, context.Log)))
+                foreach (var right in RightSource.Execute(new NodeExecutionContext(context, innerParameterTypes, innerParameters)))
                 {
                     if (rightSchema == null)
                     {
@@ -183,7 +183,7 @@ public override IDataExecutionPlanNodeInternal FoldQuery(NodeCompilationContext
             LeftSource.Parent = this;
 
             var innerParameterTypes = GetInnerParameterTypes(leftSchema, context.ParameterTypes);
-            var innerContext = new NodeCompilationContext(context.DataSources, context.Options, innerParameterTypes, context.Log);
+            var innerContext = new NodeCompilationContext(context.Session, context.Options, innerParameterTypes, context.Log);
             var rightSchema = RightSource.GetSchema(innerContext);
             RightSource = RightSource.FoldQuery(innerContext, hints);
             RightSource.Parent = this;
@@ -329,7 +329,7 @@ public override void AddRequiredColumns(NodeCompilationContext context, IList<st
                 .Distinct(StringComparer.OrdinalIgnoreCase)
                 .ToList();
             var innerParameterTypes = GetInnerParameterTypes(leftSchema, context.ParameterTypes);
-            var innerContext = new NodeCompilationContext(context.DataSources, context.Options, innerParameterTypes, context.Log);
+            var innerContext = new NodeCompilationContext(context.Session, context.Options, innerParameterTypes, context.Log);
             var rightSchema = RightSource.GetSchema(innerContext);
             var rightColumns = requiredColumns.Where(col => OutputRightSchema)
                 .Concat(criteriaCols)
@@ -346,7 +346,7 @@ protected override INodeSchema GetRightSchema(NodeCompilationContext context)
         {
             var leftSchema = LeftSource.GetSchema(context);
             var innerParameterTypes = GetInnerParameterTypes(leftSchema, context.ParameterTypes);
-            var innerContext = new NodeCompilationContext(context.DataSources, context.Options, innerParameterTypes, context.Log);
+            var innerContext = new NodeCompilationContext(context.Session, context.Options, innerParameterTypes, context.Log);
             return RightSource.GetSchema(innerContext);
         }
 
@@ -356,7 +356,7 @@ protected override RowCountEstimate EstimateRowsOutInternal(NodeCompilationConte
             ParseEstimate(leftEstimate, out var leftMin, out var leftMax, out var leftIsRange);
             var leftSchema = LeftSource.GetSchema(context);
             var innerParameterTypes = GetInnerParameterTypes(leftSchema, context.ParameterTypes);
-            var innerContext = new NodeCompilationContext(context.DataSources, context.Options, innerParameterTypes, context.Log);
+            var innerContext = new NodeCompilationContext(context.Session, context.Options, innerParameterTypes, context.Log);
 
             var rightEstimate = RightSource.EstimateRowsOut(innerContext);
             ParseEstimate(rightEstimate, out var rightMin, out var rightMax, out var rightIsRange);
diff --git a/MarkMpn.Sql4Cds.Engine/ExecutionPlan/OffsetFetchNode.cs b/MarkMpn.Sql4Cds.Engine/ExecutionPlan/OffsetFetchNode.cs
index afc53e5e..2cb5924d 100644
--- a/MarkMpn.Sql4Cds.Engine/ExecutionPlan/OffsetFetchNode.cs
+++ b/MarkMpn.Sql4Cds.Engine/ExecutionPlan/OffsetFetchNode.cs
@@ -36,8 +36,8 @@ protected override IEnumerable<Entity> ExecuteInternal(NodeExecutionContext cont
         {
             var expressionCompilationContext = new ExpressionCompilationContext(context, null, null);
             var expressionExecutionContext = new ExpressionExecutionContext(context);
-            var offset = SqlTypeConverter.ChangeType<int>(Offset.Compile(expressionCompilationContext)(expressionExecutionContext));
-            var fetch = SqlTypeConverter.ChangeType<int>(Fetch.Compile(expressionCompilationContext)(expressionExecutionContext));
+            var offset = SqlTypeConverter.ChangeType<int>(Offset.Compile(expressionCompilationContext)(expressionExecutionContext), expressionExecutionContext);
+            var fetch = SqlTypeConverter.ChangeType<int>(Fetch.Compile(expressionCompilationContext)(expressionExecutionContext), expressionExecutionContext);
 
             if (offset < 0)
                 throw new QueryExecutionException(Sql4CdsError.Create(10742, null));
@@ -65,7 +65,7 @@ public override IDataExecutionPlanNodeInternal FoldQuery(NodeCompilationContext
             Source = Source.FoldQuery(context, hints);
             Source.Parent = this;
 
-            var expressionCompilationContext = new ExpressionCompilationContext(context.DataSources, context.Options, null, null, null);
+            var expressionCompilationContext = new ExpressionCompilationContext(context, null, null);
             
             if (!Offset.IsConstantValueExpression(expressionCompilationContext, out var offsetLiteral) ||
                 !Fetch.IsConstantValueExpression(expressionCompilationContext, out var fetchLiteral))
@@ -78,8 +78,8 @@ public override IDataExecutionPlanNodeInternal FoldQuery(NodeCompilationContext
                     return this;
 
                 var expressionExecutionContext = new ExpressionExecutionContext(expressionCompilationContext);
-                var offset = SqlTypeConverter.ChangeType<int>(offsetLiteral.Compile(expressionCompilationContext)(expressionExecutionContext));
-                var count = SqlTypeConverter.ChangeType<int>(fetchLiteral.Compile(expressionCompilationContext)(expressionExecutionContext));
+                var offset = SqlTypeConverter.ChangeType<int>(offsetLiteral.Compile(expressionCompilationContext)(expressionExecutionContext), expressionExecutionContext);
+                var count = SqlTypeConverter.ChangeType<int>(fetchLiteral.Compile(expressionCompilationContext)(expressionExecutionContext), expressionExecutionContext);
                 var page = offset / count;
 
                 if (page * count == offset && count <= 5000)
diff --git a/MarkMpn.Sql4Cds.Engine/ExecutionPlan/OpenJsonNode.cs b/MarkMpn.Sql4Cds.Engine/ExecutionPlan/OpenJsonNode.cs
index 86c3d0fd..0cfaf933 100644
--- a/MarkMpn.Sql4Cds.Engine/ExecutionPlan/OpenJsonNode.cs
+++ b/MarkMpn.Sql4Cds.Engine/ExecutionPlan/OpenJsonNode.cs
@@ -15,7 +15,7 @@ class OpenJsonNode : BaseDataNode
         private Func<ExpressionExecutionContext, object> _jsonExpression;
         private Func<ExpressionExecutionContext, object> _pathExpression;
         private Collation _jsonCollation;
-        private List<Func<INullable, INullable>> _conversions;
+        private List<Func<INullable, ExpressionExecutionContext, INullable>> _conversions;
 
         private static readonly Collation _keyCollation;
 
@@ -279,7 +279,7 @@ protected override IEnumerable<Entity> ExecuteInternal(NodeExecutionContext cont
                     }
                     else
                     {
-                        yield return TokenToEntity(prop.Value, schema, mappings);
+                        yield return TokenToEntity(prop.Value, schema, mappings, eec);
                     }
                 }
             }
@@ -304,7 +304,7 @@ protected override IEnumerable<Entity> ExecuteInternal(NodeExecutionContext cont
                     }
                     else
                     {
-                        yield return TokenToEntity(item, schema, mappings);
+                        yield return TokenToEntity(item, schema, mappings, eec);
                     }
 
                     i++;
@@ -319,7 +319,7 @@ protected override IEnumerable<Entity> ExecuteInternal(NodeExecutionContext cont
             }
         }
 
-        private Entity TokenToEntity(JsonElement token, INodeSchema schema, JsonPath[] mappings)
+        private Entity TokenToEntity(JsonElement token, INodeSchema schema, JsonPath[] mappings, ExpressionExecutionContext context)
         {
             var result = new Entity();
 
@@ -373,7 +373,7 @@ private Entity TokenToEntity(JsonElement token, INodeSchema schema, JsonPath[] m
                 }
 
                 var sqlStringValue = Collation.USEnglish.ToSqlString(stringValue);
-                var sqlValue = _conversions[i](sqlStringValue);
+                var sqlValue = _conversions[i](sqlStringValue, context);
 
                 result[PrefixWithAlias(Schema[i].ColumnDefinition.ColumnIdentifier.Value, null)] = sqlValue;
             }
diff --git a/MarkMpn.Sql4Cds.Engine/ExecutionPlan/PartitionedAggregateNode.cs b/MarkMpn.Sql4Cds.Engine/ExecutionPlan/PartitionedAggregateNode.cs
index bbc31602..393c0303 100644
--- a/MarkMpn.Sql4Cds.Engine/ExecutionPlan/PartitionedAggregateNode.cs
+++ b/MarkMpn.Sql4Cds.Engine/ExecutionPlan/PartitionedAggregateNode.cs
@@ -68,7 +68,7 @@ private int GetMaxDOP(NodeCompilationContext context, IList<OptimizerHint> query
             if (fetchXmlNode.DataSource == null)
                 return 1;
 
-            if (!context.DataSources.TryGetValue(fetchXmlNode.DataSource, out var dataSource))
+            if (!context.Session.DataSources.TryGetValue(fetchXmlNode.DataSource, out var dataSource))
                 throw new NotSupportedQueryFragmentException("Unknown datasource");
 
             return ParallelismHelper.GetMaxDOP(dataSource, context, queryHints);
@@ -96,7 +96,7 @@ protected override IEnumerable<Entity> ExecuteInternal(NodeExecutionContext cont
             var fetchXmlNode = (FetchXmlScan)Source.Clone();
 
             var name = fetchXmlNode.Entity.name;
-            var meta = context.DataSources[fetchXmlNode.DataSource].Metadata[name];
+            var meta = context.Session.DataSources[fetchXmlNode.DataSource].Metadata[name];
             context.Options.Progress(0, $"Partitioning {GetDisplayName(0, meta)}...");
 
             // Get the minimum and maximum primary keys from the source
@@ -143,7 +143,7 @@ protected override IEnumerable<Entity> ExecuteInternal(NodeExecutionContext cont
             SplitPartition(fullRange);
 
             // Multi-thread where possible
-            var org = context.DataSources[fetchXmlNode.DataSource].Connection;
+            var org = context.Session.DataSources[fetchXmlNode.DataSource].Connection;
             _lock = new object();
 
 #if NETCOREAPP
@@ -172,10 +172,10 @@ protected override IEnumerable<Entity> ExecuteInternal(NodeExecutionContext cont
                             [fetchXmlNode.DataSource] = new DataSource
                             {
                                 Connection = svc?.Clone() ?? org,
-                                Metadata = context.DataSources[fetchXmlNode.DataSource].Metadata,
+                                Metadata = context.Session.DataSources[fetchXmlNode.DataSource].Metadata,
                                 Name = fetchXmlNode.DataSource,
-                                TableSizeCache = context.DataSources[fetchXmlNode.DataSource].TableSizeCache,
-                                MessageCache = context.DataSources[fetchXmlNode.DataSource].MessageCache
+                                TableSizeCache = context.Session.DataSources[fetchXmlNode.DataSource].TableSizeCache,
+                                MessageCache = context.Session.DataSources[fetchXmlNode.DataSource].MessageCache
                             }
                         };
 
@@ -199,7 +199,7 @@ protected override IEnumerable<Entity> ExecuteInternal(NodeExecutionContext cont
                                 partitionParameterValues[kvp.Key] = kvp.Value;
                         }
 
-                        var partitionContext = new NodeExecutionContext(context.DataSources, context.Options, context.ParameterTypes, partitionParameterValues, context.Log);
+                        var partitionContext = new NodeExecutionContext(context, context.ParameterTypes, partitionParameterValues);
 
                         return new { Context = partitionContext, Fetch = fetch };
                     },
@@ -335,7 +335,7 @@ private void ExecuteAggregate(NodeExecutionContext context, ExpressionExecutionC
                     expressionContext.Entity = entity;
 
                     foreach (var func in values.Values)
-                        func.AggregateFunction.NextPartition(func.State);
+                        func.AggregateFunction.NextPartition(func.State, expressionContext);
                 }
             }
         }
diff --git a/MarkMpn.Sql4Cds.Engine/ExecutionPlan/RetrieveTotalRecordCountNode.cs b/MarkMpn.Sql4Cds.Engine/ExecutionPlan/RetrieveTotalRecordCountNode.cs
index 731e3522..87348327 100644
--- a/MarkMpn.Sql4Cds.Engine/ExecutionPlan/RetrieveTotalRecordCountNode.cs
+++ b/MarkMpn.Sql4Cds.Engine/ExecutionPlan/RetrieveTotalRecordCountNode.cs
@@ -29,7 +29,7 @@ class RetrieveTotalRecordCountNode : BaseDataNode
 
         protected override IEnumerable<Entity> ExecuteInternal(NodeExecutionContext context)
         {
-            if (!context.DataSources.TryGetValue(DataSource, out var dataSource))
+            if (!context.Session.DataSources.TryGetValue(DataSource, out var dataSource))
                 throw new QueryExecutionException("Missing datasource " + DataSource);
 
             var count = ((RetrieveTotalRecordCountResponse)dataSource.Connection.Execute(new RetrieveTotalRecordCountRequest { EntityNames = new[] { EntityName } })).EntityRecordCountCollection[EntityName];
diff --git a/MarkMpn.Sql4Cds.Engine/ExecutionPlan/RevertNode.cs b/MarkMpn.Sql4Cds.Engine/ExecutionPlan/RevertNode.cs
index ee2b69e2..0fbfa131 100644
--- a/MarkMpn.Sql4Cds.Engine/ExecutionPlan/RevertNode.cs
+++ b/MarkMpn.Sql4Cds.Engine/ExecutionPlan/RevertNode.cs
@@ -63,7 +63,7 @@ public void Execute(NodeExecutionContext context, out int recordsAffected, out s
             {
                 using (_timer.Run())
                 {
-                    if (!context.DataSources.TryGetValue(DataSource, out var dataSource))
+                    if (!context.Session.DataSources.TryGetValue(DataSource, out var dataSource))
                         throw new QueryExecutionException("Missing datasource " + DataSource);
 
 #if NETCOREAPP
diff --git a/MarkMpn.Sql4Cds.Engine/ExecutionPlan/SelectNode.cs b/MarkMpn.Sql4Cds.Engine/ExecutionPlan/SelectNode.cs
index 1f93ac0d..ef2f2528 100644
--- a/MarkMpn.Sql4Cds.Engine/ExecutionPlan/SelectNode.cs
+++ b/MarkMpn.Sql4Cds.Engine/ExecutionPlan/SelectNode.cs
@@ -111,7 +111,7 @@ internal static void FoldFetchXmlColumns(IDataExecutionPlanNode source, List<Sel
         {
             if (source is FetchXmlScan fetchXml)
             {
-                if (!context.DataSources.TryGetValue(fetchXml.DataSource, out var dataSource))
+                if (!context.Session.DataSources.TryGetValue(fetchXml.DataSource, out var dataSource))
                     throw new NotSupportedQueryFragmentException("Missing datasource " + fetchXml.DataSource);
 
                 // Check if there are any aliases we can apply to the source FetchXml
diff --git a/MarkMpn.Sql4Cds.Engine/ExecutionPlan/SetDateFormatNode.cs b/MarkMpn.Sql4Cds.Engine/ExecutionPlan/SetDateFormatNode.cs
new file mode 100644
index 00000000..5463d5f9
--- /dev/null
+++ b/MarkMpn.Sql4Cds.Engine/ExecutionPlan/SetDateFormatNode.cs
@@ -0,0 +1,82 @@
+using System;
+using System.Collections.Generic;
+using System.ComponentModel;
+using System.Data.SqlTypes;
+using System.Linq;
+using Microsoft.SqlServer.TransactSql.ScriptDom;
+
+namespace MarkMpn.Sql4Cds.Engine.ExecutionPlan
+{
+    internal class SetDateFormatNode : BaseNode, IDmlQueryExecutionPlanNode
+    {
+        private Func<ExpressionExecutionContext, object> _dateFormat;
+        private int _executionCount;
+        private readonly Timer _timer = new Timer();
+
+        public SetDateFormatNode(ScalarExpression expression)
+        {
+            DateFormat = expression;
+        }
+
+        [Category("Settings")]
+        [Description("The date format to use when parsing dates")]
+        public ScalarExpression DateFormat { get; set; }
+
+        [Browsable(false)]
+        public string Sql { get; set; }
+
+        [Browsable(false)]
+        public int Index { get; set; }
+
+        [Browsable(false)]
+        public int Length { get; set; }
+
+        [Browsable(false)]
+        public int LineNumber { get; set; }
+
+        public override int ExecutionCount => _executionCount;
+
+        public override TimeSpan Duration => _timer.Duration;
+
+        public override void AddRequiredColumns(NodeCompilationContext context, IList<string> requiredColumns)
+        {
+        }
+
+        public IRootExecutionPlanNodeInternal[] FoldQuery(NodeCompilationContext context, IList<OptimizerHint> hints)
+        {
+            _dateFormat = DateFormat.Compile(new ExpressionCompilationContext(context, null, null));
+            return new[] { this };
+        }
+
+        public void Execute(NodeExecutionContext context, out int recordsAffected, out string message)
+        {
+            _executionCount++;
+
+            using (_timer.Run())
+            {
+                var formatString = ((SqlString)_dateFormat(new ExpressionExecutionContext(context))).Value;
+
+                if (!Enum.TryParse<DateFormat>(formatString, out var dateFormat))
+                    throw new QueryExecutionException(Sql4CdsError.InvalidDateFormat(DateFormat, formatString));
+
+                context.Session.DateFormat = dateFormat;
+            }
+
+            recordsAffected = -1;
+            message = null;
+        }
+
+        public override IEnumerable<IExecutionPlanNode> GetSources()
+        {
+            return Enumerable.Empty<IExecutionPlanNode>();
+        }
+
+        public object Clone()
+        {
+            return new SetDateFormatNode(DateFormat)
+            {
+                _dateFormat = _dateFormat,
+            };
+        }
+    }
+}
diff --git a/MarkMpn.Sql4Cds.Engine/ExecutionPlan/SortNode.cs b/MarkMpn.Sql4Cds.Engine/ExecutionPlan/SortNode.cs
index 57807164..2b5588af 100644
--- a/MarkMpn.Sql4Cds.Engine/ExecutionPlan/SortNode.cs
+++ b/MarkMpn.Sql4Cds.Engine/ExecutionPlan/SortNode.cs
@@ -266,10 +266,10 @@ private IDataExecutionPlanNodeInternal FoldSorts(NodeCompilationContext context)
             var canFold = fetchXml != null;
             DataSource dataSource = null;
 
-            if (canFold && fetchXml.RequiresCustomPaging(context.DataSources))
+            if (canFold && fetchXml.RequiresCustomPaging(context.Session.DataSources))
                 canFold = false;
 
-            if (canFold && !context.DataSources.TryGetValue(fetchXml.DataSource, out dataSource))
+            if (canFold && !context.Session.DataSources.TryGetValue(fetchXml.DataSource, out dataSource))
                 throw new QueryExecutionException("Missing datasource " + fetchXml.DataSource);
 
             var isAuditOrElastic = fetchXml != null && (fetchXml.Entity.name == "audit" || dataSource != null && dataSource.Metadata[fetchXml.Entity.name].DataProviderId == DataProviders.ElasticDataProvider);
diff --git a/MarkMpn.Sql4Cds.Engine/ExecutionPlan/SqlNode.cs b/MarkMpn.Sql4Cds.Engine/ExecutionPlan/SqlNode.cs
index 187ef022..1ac26485 100644
--- a/MarkMpn.Sql4Cds.Engine/ExecutionPlan/SqlNode.cs
+++ b/MarkMpn.Sql4Cds.Engine/ExecutionPlan/SqlNode.cs
@@ -9,8 +9,12 @@
 using System.Linq;
 using System.Text;
 using System.Threading.Tasks;
+using MarkMpn.Sql4Cds.Engine.FetchXml;
+using MarkMpn.Sql4Cds.Engine.Visitors;
 using Microsoft.SqlServer.TransactSql.ScriptDom;
 using Microsoft.Xrm.Sdk;
+using Microsoft.Xrm.Sdk.Metadata;
+
 #if NETCOREAPP
 using Microsoft.PowerPlatform.Dataverse.Client;
 #else
@@ -53,6 +57,8 @@ public SqlNode() { }
         [Browsable(false)]
         public HashSet<string> Parameters { get; private set; } = new HashSet<string>(StringComparer.OrdinalIgnoreCase);
 
+        internal SelectStatement SelectStatement { get; set; }
+
         public override void AddRequiredColumns(NodeCompilationContext context, IList<string> requiredColumns)
         {
         }
@@ -65,7 +71,7 @@ public DbDataReader Execute(NodeExecutionContext context, CommandBehavior behavi
             {
                 try
                 {
-                    if (!context.DataSources.TryGetValue(DataSource, out var dataSource))
+                    if (!context.Session.DataSources.TryGetValue(DataSource, out var dataSource))
                         throw new QueryExecutionException("Missing datasource " + DataSource);
 
                     if (context.Options.UseLocalTimeZone)
@@ -89,7 +95,7 @@ public DbDataReader Execute(NodeExecutionContext context, CommandBehavior behavi
 
                     var cmd = con.CreateCommand();
                     cmd.CommandTimeout = (int)TimeSpan.FromMinutes(2).TotalSeconds;
-                    cmd.CommandText = ApplyCommandBehavior(Sql, behavior, context.Options);
+                    cmd.CommandText = ApplyCommandBehavior(Sql, behavior, context);
 
                     foreach (var paramValue in context.ParameterValues)
                     {
@@ -145,13 +151,19 @@ public DbDataReader Execute(NodeExecutionContext context, CommandBehavior behavi
             }
         }
 
-        internal static string ApplyCommandBehavior(string sql, CommandBehavior behavior, IQueryExecutionOptions options)
+        internal static string ApplyCommandBehavior(string sql, CommandBehavior behavior, NodeExecutionContext context)
         {
+            if (context.Session.DateFormat != DateFormat.mdy)
+            {
+                // mdy is the default format for the TDS Endpoint, so we need to switch it as necessary
+                sql = "SET DATEFORMAT " + context.Session.DateFormat.ToString() + ";\r\n" + sql;
+            }
+
             if (behavior == CommandBehavior.Default)
                 return sql;
 
             // TDS Endpoint doesn't support command behavior flags, so fake them by modifying the SQL query
-            var dom = new TSql160Parser(options.QuotedIdentifiers);
+            var dom = new TSql160Parser(context.Options.QuotedIdentifiers);
             var script = (TSqlScript) dom.Parse(new StringReader(sql), out _);
 
             if (behavior.HasFlag(CommandBehavior.SchemaOnly))
@@ -225,6 +237,144 @@ public override IEnumerable<IExecutionPlanNode> GetSources()
             return Array.Empty<IExecutionPlanNode>();
         }
 
+        internal IExecutionPlanNodeInternal FoldDmlSource(NodeCompilationContext context, IList<OptimizerHint> hints, string logicalName, string[] requiredColumns, string[] keyAttributes)
+        {
+            if (!(SelectStatement?.QueryExpression is QuerySpecification querySpec))
+                return this;
+
+            if (querySpec.FromClause == null || querySpec.FromClause.TableReferences.Count != 1 || !(querySpec.FromClause.TableReferences[0] is NamedTableReference table))
+                return this;
+
+            if (table.SchemaObject.BaseIdentifier.Value != logicalName)
+                return this;
+
+            if (querySpec.WhereClause == null || querySpec.WhereClause.SearchCondition == null)
+                return this;
+
+            var filterVisitor = new SimpleFilterVisitor();
+            querySpec.WhereClause.SearchCondition.Accept(filterVisitor);
+
+            if (filterVisitor.BinaryType == null)
+                return this;
+
+            var dataSource = context.Session.DataSources[DataSource];
+            var metadata = dataSource.Metadata[logicalName];
+            var conditions = filterVisitor.Conditions.ToList();
+            var ecc = new ExpressionCompilationContext(context, null, null);
+
+            if (!TryGetDmlSchema(dataSource, metadata, querySpec, new ExpressionCompilationContext(context, null, null), out var schema, out var literalValues))
+                return this;
+
+            // Every column must either be a literal or a key attribute
+            if (requiredColumns.Except(literalValues.Keys).Except(keyAttributes).Any())
+                return this;
+
+            var constantScan = new ConstantScanNode();
+
+            foreach (var col in requiredColumns)
+                constantScan.Schema[col.SplitMultiPartIdentifier().Last()] = new ColumnDefinition(schema[col], true, false);
+
+            // We can handle compound keys, but only if they are all ANDed together
+            if (keyAttributes.Length > 1 && filterVisitor.BinaryType == BooleanBinaryExpressionType.And)
+            {
+                var values = new Dictionary<string, ScalarExpression>();
+
+                foreach (var col in requiredColumns)
+                {
+                    if (literalValues.ContainsKey(col))
+                        continue;
+
+                    var condition = conditions.FirstOrDefault(c => c.attribute == col.SplitMultiPartIdentifier().Last());
+                    if (condition == null)
+                        return this;
+
+                    if (condition.@operator != @operator.eq)
+                        return this;
+
+                    var attribute = metadata.Attributes.Single(a => a.LogicalName == condition.attribute);
+                    values[condition.attribute] = attribute.GetDmlValue(condition.value, condition.IsVariable, ecc, dataSource);
+                }
+
+                constantScan.Values.Add(values);
+
+                AddLiteralValues(constantScan, literalValues);
+                return constantScan;
+            }
+
+            // We can also handle multiple values for a single key being ORed together
+            else if (keyAttributes.Length == 1 &&
+                conditions.All(c => c.attribute == metadata.PrimaryIdAttribute) &&
+                conditions.All(c => c.@operator == @operator.eq || c.@operator == @operator.@in) &&
+                (conditions.Count == 1 || filterVisitor.BinaryType == BooleanBinaryExpressionType.Or))
+            {
+                foreach (var condition in conditions)
+                {
+                    var attribute = metadata.Attributes.Single(a => a.LogicalName == condition.attribute);
+
+                    if (condition.@operator == @operator.eq)
+                    {
+                        constantScan.Values.Add(new Dictionary<string, ScalarExpression> { [condition.attribute] = attribute.GetDmlValue(condition.value, condition.IsVariable, ecc, dataSource) });
+                    }
+                    else if (condition.@operator == @operator.@in)
+                    {
+                        foreach (var value in condition.Items)
+                            constantScan.Values.Add(new Dictionary<string, ScalarExpression> { [condition.attribute] = attribute.GetDmlValue(value.Value, value.IsVariable, ecc, dataSource) });
+                    }
+                }
+
+                AddLiteralValues(constantScan, literalValues);
+                return constantScan;
+            }
+
+            return this;
+        }
+
+        private void AddLiteralValues(ConstantScanNode constantScan, Dictionary<string, ScalarExpression> literalValues)
+        {
+            foreach (var row in constantScan.Values)
+            {
+                foreach (var value in literalValues)
+                {
+                    row[value.Key] = value.Value;
+                }
+            }
+        }
+
+        private bool TryGetDmlSchema(DataSource dataSource, EntityMetadata metadata, QuerySpecification querySpec, ExpressionCompilationContext context, out Dictionary<string, DataTypeReference> schema, out Dictionary<string, ScalarExpression> literalValues)
+        {
+            schema = new Dictionary<string, DataTypeReference>(StringComparer.OrdinalIgnoreCase);
+            literalValues = new Dictionary<string, ScalarExpression>(StringComparer.OrdinalIgnoreCase);
+
+            foreach (var select in querySpec.SelectElements)
+            {
+                if (!(select is SelectScalarExpression scalar))
+                    return false;
+
+                if (!scalar.Expression.GetColumns().Any() && scalar.ColumnName?.Value != null)
+                {
+                    scalar.Expression.GetType(context, out var literalType);
+                    schema[scalar.ColumnName.Value] = literalType;
+                    literalValues[scalar.ColumnName.Value] = scalar.Expression;
+                    continue;
+                }
+
+                if (!(scalar.Expression is ColumnReferenceExpression col))
+                    return false;
+
+                var attribute = metadata.Attributes.SingleOrDefault(a => a.LogicalName.Equals(col.MultiPartIdentifier.Identifiers.Last().Value, StringComparison.OrdinalIgnoreCase));
+
+                if (attribute == null)
+                    return false;
+
+                var type = attribute.GetAttributeSqlType(dataSource, false);
+                var name = scalar.ColumnName?.Value ?? attribute.LogicalName;
+
+                schema[name] = type;
+            }
+
+            return true;
+        }
+
         public override string ToString()
         {
             return "TDS Endpoint";
@@ -239,7 +389,8 @@ public object Clone()
                 Index = Index,
                 Length = Length,
                 LineNumber = LineNumber,
-                Parameters = Parameters
+                Parameters = Parameters,
+                SelectStatement = SelectStatement
             };
         }
     }
diff --git a/MarkMpn.Sql4Cds.Engine/ExecutionPlan/SqlTypeConverter.cs b/MarkMpn.Sql4Cds.Engine/ExecutionPlan/SqlTypeConverter.cs
index 42e9b8fa..aff5bc84 100644
--- a/MarkMpn.Sql4Cds.Engine/ExecutionPlan/SqlTypeConverter.cs
+++ b/MarkMpn.Sql4Cds.Engine/ExecutionPlan/SqlTypeConverter.cs
@@ -52,8 +52,8 @@ class SqlTypeConverter
 
         private static readonly IDictionary<Type, INullable> _nullValues;
         private static readonly CultureInfo _hijriCulture;
-        private static ConcurrentDictionary<string, Func<object, object>> _conversions;
-        private static ConcurrentDictionary<string, Func<INullable, INullable>> _sqlConversions;
+        private static ConcurrentDictionary<string, Func<object, ExpressionExecutionContext, object>> _conversions;
+        private static ConcurrentDictionary<string, Func<INullable, ExpressionExecutionContext, INullable>> _sqlConversions;
         private static Dictionary<Type, Type> _netToSqlTypeConversions;
         private static Dictionary<Type, Func<DataSource, object, DataTypeReference, INullable>> _netToSqlTypeConversionFuncs;
         private static Dictionary<Type, Type> _sqlToNetTypeConversions;
@@ -80,6 +80,7 @@ static SqlTypeConverter()
                 [typeof(SqlDate)] = SqlDate.Null,
                 [typeof(SqlDateTime2)] = SqlDateTime2.Null,
                 [typeof(SqlDateTimeOffset)] = SqlDateTimeOffset.Null,
+                [typeof(SqlSmallDateTime)] = SqlSmallDateTime.Null,
                 [typeof(SqlTime)] = SqlTime.Null,
                 [typeof(SqlXml)] = SqlXml.Null,
                 [typeof(SqlVariant)] = SqlVariant.Null
@@ -88,8 +89,8 @@ static SqlTypeConverter()
             _hijriCulture = (CultureInfo)CultureInfo.GetCultureInfo("ar-JO").Clone();
             _hijriCulture.DateTimeFormat.Calendar = new HijriCalendar();
 
-            _conversions = new ConcurrentDictionary<string, Func<object, object>>();
-            _sqlConversions = new ConcurrentDictionary<string, Func<INullable, INullable>>();
+            _conversions = new ConcurrentDictionary<string, Func<object, ExpressionExecutionContext, object>>();
+            _sqlConversions = new ConcurrentDictionary<string, Func<INullable, ExpressionExecutionContext, INullable>>();
 
             _netToSqlTypeConversions = new Dictionary<Type, Type>();
             _netToSqlTypeConversionFuncs = new Dictionary<Type, Func<DataSource, object, DataTypeReference, INullable>>();
@@ -110,9 +111,10 @@ static SqlTypeConverter()
             AddTypeConversion<SqlSingle, float>((ds, v, dt) => v, v => v.Value);
             AddNullableTypeConversion<SqlString, string>((ds, v, dt) => ((SqlDataTypeReferenceWithCollation)dt).Collation.ToSqlString(v), v => v.Value);
             AddTypeConversion<SqlMoney, decimal>((ds, v, dt) => v, v => v.Value);
-            AddTypeConversion<SqlDate, DateTime>((ds, v, dt) => (SqlDateTime)v, v => v.Value);
-            AddTypeConversion<SqlDateTime2, DateTime>((ds, v, dt) => (SqlDateTime)v, v => v.Value);
+            AddTypeConversion<SqlDate, DateTime>((ds, v, dt) => new SqlDate(v), v => v.Value);
+            AddTypeConversion<SqlDateTime2, DateTime>((ds, v, dt) => new SqlDateTime2(v), v => v.Value);
             AddTypeConversion<SqlDateTimeOffset, DateTimeOffset>((ds, v, dt) => new SqlDateTimeOffset(v), v => v.Value);
+            AddTypeConversion<SqlSmallDateTime, DateTime>((ds, v, dt) => new SqlSmallDateTime(v), v => v.Value);
             AddTypeConversion<SqlTime, TimeSpan>((ds, v, dt) => new SqlTime(v), v => v.Value);
             AddNullableTypeConversion<SqlXml, string>((ds, v, dt) => new SqlXml(new MemoryStream(Encoding.GetEncoding("utf-16").GetBytes(v))), v => v.Value);
 
@@ -461,30 +463,46 @@ public static bool CanChangeTypeExplicit(DataTypeReference from, DataTypeReferen
         /// Produces the required expression to convert values to a specific type
         /// </summary>
         /// <param name="expr">The expression that generates the values to convert</param>
+        /// <param name="context">The expression which contains the <see cref="ExpressionExecutionContext"/> the expression will be evaluated in</param>
         /// <param name="to">The type to convert to</param>
-        /// <param name="contextParam">The expression which contains the <see cref="ExpressionExecutionContext"/> the expression will be evaluated in</param>
         /// <returns>An expression to generate values of the required type</returns>
-        public static Expression Convert(Expression expr, Type to)
+        public static Expression Convert(Expression expr, Expression context, Type to)
         {
-            if (expr.Type == typeof(SqlDateTime) && (to == typeof(SqlBoolean) || to == typeof(SqlByte) || to == typeof(SqlInt16) || to == typeof(SqlInt32) || to == typeof(SqlInt64) || to == typeof(SqlDecimal) || to == typeof(SqlSingle) || to == typeof(SqlDouble)))
+            if ((expr.Type == typeof(SqlDateTime) || expr.Type == typeof(SqlSmallDateTime)) && (to == typeof(SqlBoolean) || to == typeof(SqlByte) || to == typeof(SqlInt16) || to == typeof(SqlInt32) || to == typeof(SqlInt64) || to == typeof(SqlDecimal) || to == typeof(SqlSingle) || to == typeof(SqlDouble)))
             {
+                // Conversion from datetime types to numeric types uses the number of days since 1900-01-01
+                Expression converted;
+
+                if (expr.Type == typeof(SqlDateTime))
+                    converted = Expression.Convert(expr, typeof(DateTime));
+                else
+                    converted = Expression.PropertyOrField(expr, nameof(SqlSmallDateTime.Value));
+
+                converted = Expression.PropertyOrField(
+                    Expression.Subtract(
+                        converted,
+                        Expression.Constant(new DateTime(1900, 1, 1))
+                    ),
+                    nameof(TimeSpan.TotalDays)
+                );
+
+                // Round the value when converting from datetime to an integer type, rather than
+                // using the standard double -> int truncation
+                if (to == typeof(SqlBoolean) || to == typeof(SqlByte) || to == typeof(SqlInt16) || to == typeof(SqlInt32) || to == typeof(SqlInt64))
+                {
+                    converted = Expr.Call(() => Math.Round(Expr.Arg<double>()), converted);
+                }
+
+                // Convert the result to a SqlDouble and handle null values
                 expr = Expression.Condition(
                     Expression.PropertyOrField(expr, nameof(SqlDateTime.IsNull)),
                     Expression.Constant(SqlDouble.Null),
-                    Expression.Convert(
-                        Expression.PropertyOrField(
-                            Expression.Subtract(
-                                Expression.Convert(expr, typeof(DateTime)),
-                                Expression.Constant(new DateTime(1900, 1, 1))
-                            ),
-                            nameof(TimeSpan.TotalDays)
-                        ),
-                        typeof(SqlDouble)
+                    Expression.Convert(converted, typeof(SqlDouble)
                     )
                 );
             }
 
-            if ((expr.Type == typeof(SqlBoolean) || expr.Type == typeof(SqlByte) || expr.Type == typeof(SqlInt16) || expr.Type == typeof(SqlInt32) || expr.Type == typeof(SqlInt64) || expr.Type == typeof(SqlDecimal) || expr.Type == typeof(SqlSingle) || expr.Type == typeof(SqlDouble)) && to == typeof(SqlDateTime))
+            if ((expr.Type == typeof(SqlBoolean) || expr.Type == typeof(SqlByte) || expr.Type == typeof(SqlInt16) || expr.Type == typeof(SqlInt32) || expr.Type == typeof(SqlInt64) || expr.Type == typeof(SqlDecimal) || expr.Type == typeof(SqlSingle) || expr.Type == typeof(SqlDouble)) && (to == typeof(SqlDateTime) || to == typeof(SqlSmallDateTime)))
             {
                 expr = Expression.Condition(
                     NullCheck(expr),
@@ -520,6 +538,21 @@ public static Expression Convert(Expression expr, Type to)
             if (expr.Type == typeof(SqlString) && to == typeof(SqlXml))
                 expr = Expr.Call(() => ParseXml(Expr.Arg<SqlString>()), expr);
 
+            if (expr.Type == typeof(SqlString) && to == typeof(SqlTime))
+                expr = Expr.Call(() => ParseTime(Expr.Arg<SqlString>(), Expr.Arg<ExpressionExecutionContext>()), expr, context);
+
+            if (expr.Type == typeof(SqlString) && to == typeof(SqlDate))
+                expr = Expr.Call(() => ParseDate(Expr.Arg<SqlString>(), Expr.Arg<ExpressionExecutionContext>()), expr, context);
+
+            if (expr.Type == typeof(SqlString) && (to == typeof(SqlDateTime) || to == typeof(SqlSmallDateTime)))
+                expr = Expr.Call(() => ParseDateTime(Expr.Arg<SqlString>(), Expr.Arg<ExpressionExecutionContext>()), expr, context);
+
+            if (expr.Type == typeof(SqlString) && to == typeof(SqlDateTime2))
+                expr = Expr.Call(() => ParseDateTime2(Expr.Arg<SqlString>(), Expr.Arg<ExpressionExecutionContext>()), expr, context);
+
+            if (expr.Type == typeof(SqlString) && to == typeof(SqlDateTimeOffset))
+                expr = Expr.Call(() => ParseDateTimeOffset(Expr.Arg<SqlString>(), Expr.Arg<ExpressionExecutionContext>()), expr, context);
+
             if (expr.Type == typeof(SqlDecimal) && (to == typeof(SqlInt64) || to == typeof(SqlInt32) || to == typeof(SqlInt16) || to == typeof(SqlByte)))
             {
                 // Built-in conversion uses rounding, should use truncation
@@ -548,9 +581,44 @@ public static Expression Convert(Expression expr, Type to)
             return expr;
         }
 
-        private static SqlString ApplyCollation(ExpressionExecutionContext context, SqlString sqlString)
+        private static SqlTime ParseTime(SqlString value, ExpressionExecutionContext context)
+        {
+            if (!SqlDateParsing.TryParse(value.Value, context.Session.DateFormat, out SqlTime time))
+                throw new QueryExecutionException(Sql4CdsError.DateTimeParseError(null));
+
+            return time;
+        }
+
+        private static SqlDate ParseDate(SqlString value, ExpressionExecutionContext context)
         {
-            return ApplyCollation(context.PrimaryDataSource.DefaultCollation, sqlString);
+            if (!SqlDateParsing.TryParse(value.Value, context.Session.DateFormat, out SqlDate date))
+                throw new QueryExecutionException(Sql4CdsError.DateTimeParseError(null));
+
+            return date;
+        }
+
+        private static SqlDateTime ParseDateTime(SqlString value, ExpressionExecutionContext context)
+        {
+            if (!SqlDateParsing.TryParse(value.Value, context.Session.DateFormat, out SqlDateTime dateTime))
+                throw new QueryExecutionException(Sql4CdsError.DateTimeParseError(null));
+
+            return dateTime;
+        }
+
+        private static SqlDateTime2 ParseDateTime2(SqlString value, ExpressionExecutionContext context)
+        {
+            if (!SqlDateParsing.TryParse(value.Value, context.Session.DateFormat, out SqlDateTime2 dateTime2))
+                throw new QueryExecutionException(Sql4CdsError.DateTimeParseError(null));
+
+            return dateTime2;
+        }
+
+        private static SqlDateTimeOffset ParseDateTimeOffset(SqlString value, ExpressionExecutionContext context)
+        {
+            if (!SqlDateParsing.TryParse(value.Value, context.Session.DateFormat, out SqlDateTimeOffset dateTimeOffset))
+                throw new QueryExecutionException(Sql4CdsError.DateTimeParseError(null));
+
+            return dateTimeOffset;
         }
 
         private static SqlString ApplyCollation(Collation collation, SqlString sqlString)
@@ -565,13 +633,14 @@ private static SqlString ApplyCollation(Collation collation, SqlString sqlString
         /// Produces the required expression to convert values to a specific type
         /// </summary>
         /// <param name="expr">The expression that generates the values to convert</param>
+        /// <param name="context">The expression that provides the current <see cref="ExpressionExecutionContext"/> when the expression is evaluated</param>
         /// <param name="from">The type to convert from</param>
         /// <param name="to">The type to convert to</param>
         /// <param name="style">An optional parameter defining the style of the conversion</param>
         /// <param name="styleType">An optional parameter defining the type of the <paramref name="style"/> expression</param>
         /// <param name="convert">An optional parameter containing the SQL CONVERT() function call to report any errors against</param>
         /// <returns>An expression to generate values of the required type</returns>
-        public static Expression Convert(Expression expr, DataTypeReference from, DataTypeReference to, Expression style = null, DataTypeReference styleType = null, TSqlFragment convert = null, bool throwOnTruncate = false, string table = null, string column = null)
+        public static Expression Convert(Expression expr, Expression context, DataTypeReference from, DataTypeReference to, Expression style = null, DataTypeReference styleType = null, TSqlFragment convert = null, bool throwOnTruncate = false, string table = null, string column = null)
         {
             if (from.IsSameAs(to))
                 return expr;
@@ -605,20 +674,20 @@ public static Expression Convert(Expression expr, DataTypeReference from, DataTy
             // Special case for conversion to sql_variant
             if (to.IsSameAs(DataTypeHelpers.Variant))
             {
-                var ctor = typeof(SqlVariant).GetConstructor(new[] { typeof(DataTypeReference), typeof(INullable) });
-                return Expression.New(ctor, Expression.Constant(from), Expression.Convert(expr, typeof(INullable)));
+                var ctor = typeof(SqlVariant).GetConstructor(new[] { typeof(DataTypeReference), typeof(INullable), typeof(ExpressionExecutionContext) });
+                return Expression.New(ctor, Expression.Constant(from), Expression.Convert(expr, typeof(INullable)), context);
             }
 
             // Special case for conversion from sql_variant
             if (from.IsSameAs(DataTypeHelpers.Variant))
             {
-                return Expression.Convert(Expr.Call(() => Convert(Expr.Arg<SqlVariant>(), Expr.Arg<DataTypeReference>(), Expr.Arg<SqlInt32>()), expr, Expression.Constant(to), style), targetType);
+                return Expression.Convert(Expr.Call(() => Convert(Expr.Arg<SqlVariant>(), Expr.Arg<DataTypeReference>(), Expr.Arg<SqlInt32>(), Expr.Arg<ExpressionExecutionContext>()), expr, Expression.Constant(to), style, context), targetType);
             }
 
             var targetCollation = (to as SqlDataTypeReferenceWithCollation)?.Collation;
 
             if (fromSqlType != null && (fromSqlType.SqlDataTypeOption.IsDateTimeType() || fromSqlType.SqlDataTypeOption == SqlDataTypeOption.Date || fromSqlType.SqlDataTypeOption == SqlDataTypeOption.Time) && targetType == typeof(SqlString))
-                expr = Expr.Call(() => Convert(Expr.Arg<SqlDateTime>(), Expr.Arg<bool>(), Expr.Arg<bool>(), Expr.Arg<int>(), Expr.Arg<DataTypeReference>(), Expr.Arg<DataTypeReference>(), Expr.Arg<SqlInt32>(), Expr.Arg<Collation>()), Convert(expr, typeof(SqlDateTime)), Expression.Constant(fromSqlType.SqlDataTypeOption != SqlDataTypeOption.Time), Expression.Constant(fromSqlType.SqlDataTypeOption != SqlDataTypeOption.Date), Expression.Constant(from.GetScale()), Expression.Constant(from), Expression.Constant(to), style, Expression.Constant(targetCollation));
+                expr = Expr.Call(() => Convert(Expr.Arg<SqlDateTimeOffset>(), Expr.Arg<bool>(), Expr.Arg<bool>(), Expr.Arg<int>(), Expr.Arg<DataTypeReference>(), Expr.Arg<DataTypeReference>(), Expr.Arg<SqlInt32>(), Expr.Arg<Collation>()), Convert(expr, context, typeof(SqlDateTimeOffset)), Expression.Constant(fromSqlType.SqlDataTypeOption != SqlDataTypeOption.Time), Expression.Constant(fromSqlType.SqlDataTypeOption != SqlDataTypeOption.Date), Expression.Constant(from.GetScale()), Expression.Constant(from), Expression.Constant(to), style, Expression.Constant(targetCollation));
             else if ((expr.Type == typeof(SqlDouble) || expr.Type == typeof(SqlSingle)) && targetType == typeof(SqlString))
                 expr = Expr.Call(() => Convert(Expr.Arg<SqlDouble>(), Expr.Arg<SqlInt32>(), Expr.Arg<Collation>()), expr, style, Expression.Constant(targetCollation));
             else if (expr.Type == typeof(SqlMoney) && targetType == typeof(SqlString))
@@ -628,7 +697,7 @@ public static Expression Convert(Expression expr, DataTypeReference from, DataTy
 
             if (expr.Type != targetType)
             {
-                expr = Convert(expr, targetType);
+                expr = Convert(expr, context, targetType);
 
                 // Handle errors during type conversion
                 var conversionError = Expr.Call(() => Sql4CdsError.ConversionError(Expr.Arg<TSqlFragment>(), Expr.Arg<DataTypeReference>(), Expr.Arg<DataTypeReference>()), Expression.Constant(convert, typeof(TSqlFragment)), Expression.Constant(from), Expression.Constant(to));
@@ -731,7 +800,7 @@ public static Expression Convert(Expression expr, DataTypeReference from, DataTy
 
                 if (toSqlType.Parameters.Count > 0)
                 {
-                    if (!Int32.TryParse(toSqlType.Parameters[0].Value, out precision))
+                    if (!Int32.TryParse(toSqlType.Parameters[0].Value, out precision) || precision < 0)
                         throw new NotSupportedQueryFragmentException(Sql4CdsError.SyntaxError(toSqlType)) { Suggestion = "Invalid attributes specified for type " + toSqlType.SqlDataTypeOption };
 
                     if (precision < 1)
@@ -739,8 +808,11 @@ public static Expression Convert(Expression expr, DataTypeReference from, DataTy
 
                     if (toSqlType.Parameters.Count > 1)
                     {
-                        if (!Int32.TryParse(toSqlType.Parameters[1].Value, out scale))
+                        if (!Int32.TryParse(toSqlType.Parameters[1].Value, out scale) || scale < 0)
                             throw new NotSupportedQueryFragmentException(Sql4CdsError.SyntaxError(toSqlType)) { Suggestion = "Invalid attributes specified for type " + toSqlType.SqlDataTypeOption };
+
+                        if (scale > precision)
+                            throw new NotSupportedQueryFragmentException(Sql4CdsError.InvalidScale(toSqlType, 0)) { Suggestion = "Scale cannot be greater than precision" };
                     }
 
                     if (toSqlType.Parameters.Count > 2)
@@ -755,6 +827,25 @@ public static Expression Convert(Expression expr, DataTypeReference from, DataTy
                     Expression.Constant(to),
                     Expression.Constant(convert, typeof(TSqlFragment)));
             }
+            else if (expr.Type == typeof(SqlDateTime2) || expr.Type == typeof(SqlDateTimeOffset))
+            {
+                // Default scale is 7
+                var scale = 7;
+
+                if (toSqlType.Parameters.Count > 0)
+                {
+                    if (!Int32.TryParse(toSqlType.Parameters[0].Value, out scale) || scale < 0)
+                        throw new NotSupportedQueryFragmentException(Sql4CdsError.SyntaxError(toSqlType)) { Suggestion = "Invalid attributes specified for type " + toSqlType.SqlDataTypeOption };
+
+                    if (scale > 7)
+                        throw new NotSupportedQueryFragmentException(Sql4CdsError.InvalidScale(toSqlType, 1)) { Suggestion = "Scale cannot be greater than 7" };
+                }
+
+                if (expr.Type == typeof(SqlDateTime2))
+                    expr = Expr.Call(() => ApplyScale(Expr.Arg<SqlDateTime2>(), Expr.Arg<int>()), expr, Expression.Constant(scale));
+                else
+                    expr = Expr.Call(() => ApplyScale(Expr.Arg<SqlDateTimeOffset>(), Expr.Arg<int>()), expr, Expression.Constant(scale));
+            }
 
             return expr;
         }
@@ -771,6 +862,38 @@ private static SqlDecimal ApplyPrecisionScale(SqlDecimal value, int precision, i
             }
         }
 
+        private static SqlDateTime2 ApplyScale(SqlDateTime2 value, int scale)
+        {
+            if (value.IsNull)
+                return value;
+
+            var ticks = value.Value.Ticks % TimeSpan.TicksPerSecond;
+            var integerSeconds = value.Value.AddTicks(-ticks);
+
+            if (scale == 0)
+                return integerSeconds;
+
+            var fractionalSeconds = (decimal)ticks / TimeSpan.TicksPerSecond;
+            var rounded = Math.Round(fractionalSeconds, scale, MidpointRounding.AwayFromZero);
+            return integerSeconds.AddTicks((int)(rounded * TimeSpan.TicksPerSecond));
+        }
+
+        private static SqlDateTimeOffset ApplyScale(SqlDateTimeOffset value, int scale)
+        {
+            if (value.IsNull)
+                return value;
+
+            var ticks = value.Value.Ticks % TimeSpan.TicksPerSecond;
+            var integerSeconds = value.Value.AddTicks(-ticks);
+
+            if (scale == 0)
+                return integerSeconds;
+
+            var fractionalSeconds = (decimal)ticks / TimeSpan.TicksPerSecond;
+            var rounded = Math.Round(fractionalSeconds, scale, MidpointRounding.AwayFromZero);
+            return integerSeconds.AddTicks((int)(rounded * TimeSpan.TicksPerSecond));
+        }
+
         /// <summary>
         /// Converts a <see cref="SqlString"/> value from one collation to another
         /// </summary>
@@ -890,7 +1013,7 @@ private static SqlXml ParseXml(SqlString value)
         /// <param name="style">The style to apply</param>
         /// <param name="collation">The collation to use for the returned result</param>
         /// <returns>The converted string</returns>
-        private static SqlString Convert(SqlDateTime value, bool date, bool time, int timeScale, DataTypeReference fromType, DataTypeReference toType, SqlInt32 style, Collation collation)
+        private static SqlString Convert(SqlDateTimeOffset value, bool date, bool time, int timeScale, DataTypeReference fromType, DataTypeReference toType, SqlInt32 style, Collation collation)
         {
             if (value.IsNull || style.IsNull)
                 return SqlString.Null;
@@ -973,7 +1096,12 @@ private static SqlString Convert(SqlDateTime value, bool date, bool time, int ti
                 case 9:
                 case 109:
                     dateFormatString = "MMM dd yyyy";
-                    timeFormatString = "hh:mm:ss:" + new string('f', timeScale) + "tt";
+                    timeFormatString = "hh:mm:ss";
+
+                    if (timeScale > 0)
+                        timeFormatString += ":" + new string('f', timeScale);
+
+                    timeFormatString += "tt";
                     break;
 
                 case 10:
@@ -1003,12 +1131,18 @@ private static SqlString Convert(SqlDateTime value, bool date, bool time, int ti
                 case 13:
                 case 113:
                     dateFormatString = "dd MMM yyyy";
-                    timeFormatString = "HH:mm:ss:" + new string('f', timeScale);
+                    timeFormatString = "HH:mm:ss";
+
+                    if (timeScale > 0)
+                        timeFormatString += ":" + new string('f', timeScale);
                     break;
 
                 case 14:
                 case 114:
-                    timeFormatString = "HH:mm:ss:" + new string('f', timeScale);
+                    timeFormatString = "HH:mm:ss";
+
+                    if (timeScale > 0)
+                        timeFormatString += ":" + new string('f', timeScale);
                     break;
 
                 case 20:
@@ -1021,7 +1155,10 @@ private static SqlString Convert(SqlDateTime value, bool date, bool time, int ti
                 case 25:
                 case 121:
                     dateFormatString = "yyyy-MM-dd";
-                    timeFormatString = "HH:mm:ss." + new string('f', timeScale);
+                    timeFormatString = "HH:mm:ss";
+
+                    if (timeScale > 0)
+                        timeFormatString += "." + new string('f', timeScale);
                     break;
 
                 case 22:
@@ -1036,24 +1173,44 @@ private static SqlString Convert(SqlDateTime value, bool date, bool time, int ti
                 case 126:
                     dateFormatString = "yyyy-MM-dd";
                     dateTimeSeparator = "T";
-                    timeFormatString = "HH:mm:ss." + new string('F', timeScale);
+                    timeFormatString = "HH:mm:ss";
+
+                    if (timeScale > 0)
+                        timeFormatString += "." + new string('F', timeScale);
                     break;
 
                 case 127:
                     dateFormatString = "yyyy-MM-dd";
                     dateTimeSeparator = "T";
-                    timeFormatString = "HH:mm:ss." + new string('F', timeScale) + "\\Z";
+                    timeFormatString = "HH:mm:ss";
+
+                    if (timeScale > 0)
+                        timeFormatString += "." + new string('F', timeScale);
+
+                    timeFormatString += "\\Z";
                     break;
 
                 case 130:
                     dateFormatString = "dd MMMM yyyy";
-                    timeFormatString = "hh:mm:ss:" + new string('f', timeScale) + "tt";
+                    timeFormatString = "hh:mm:ss";
+
+                    if (timeScale > 0)
+                        timeFormatString += ":" + new string('f', timeScale);
+
+                    timeFormatString += "tt";
+
                     cultureInfo = _hijriCulture;
                     break;
 
                 case 131:
                     dateFormatString = "dd/MM/yyyy";
-                    timeFormatString = "HH:mm:ss:" + new string('f', timeScale) + "tt";
+                    timeFormatString = "hh:mm:ss";
+
+                    if (timeScale > 0)
+                        timeFormatString += ":" + new string('f', timeScale);
+
+                    timeFormatString += "tt";
+
                     cultureInfo = _hijriCulture;
                     break;
 
@@ -1075,8 +1232,13 @@ private static SqlString Convert(SqlDateTime value, bool date, bool time, int ti
             }
 
             if (time && !String.IsNullOrEmpty(timeFormatString))
+            {
                 formatString += timeFormatString;
 
+                if (fromType is SqlDataTypeReference sqlFromType && sqlFromType.SqlDataTypeOption == SqlDataTypeOption.DateTimeOffset)
+                    formatString += " zzz";
+            }
+
             var formatted = value.Value.ToString(formatString, cultureInfo);
             return collation.ToSqlString(formatted);
         }
@@ -1174,7 +1336,7 @@ private static SqlString Convert(SqlBinary value, Collation collation, bool unic
         /// <param name="targetType">The type to convert to</param>
         /// <param name="style">The style of the conversion</param>
         /// <returns>The underlying value of the variant converted to the target type</returns>
-        private static INullable Convert(SqlVariant variant, DataTypeReference targetType, SqlInt32 style)
+        private static INullable Convert(SqlVariant variant, DataTypeReference targetType, SqlInt32 style, ExpressionExecutionContext context)
         {
             if (variant.BaseType == null)
                 return GetNullValue(targetType.ToNetType(out _));
@@ -1186,7 +1348,7 @@ private static INullable Convert(SqlVariant variant, DataTypeReference targetTyp
                 throw new QueryExecutionException(Sql4CdsError.ExplicitConversionNotAllowed(null, variant.BaseType, targetType));
 
             var conversion = GetConversion(variant.BaseType, targetType, style.IsNull ? (int?)null : style.Value);
-            return conversion(variant.Value);
+            return conversion(variant.Value, context);
         }
 
         /// <summary>
@@ -1311,9 +1473,9 @@ public static INullable GetNullValue(Type sqlType)
         /// <typeparam name="T">The type to convert the value to</typeparam>
         /// <param name="value">The value to convert</param>
         /// <returns>The value converted to the requested type</returns>
-        public static T ChangeType<T>(object value)
+        public static T ChangeType<T>(object value, ExpressionExecutionContext context)
         {
-            return (T)ChangeType(value, typeof(T));
+            return (T)ChangeType(value, typeof(T), context);
         }
 
         /// <summary>
@@ -1323,13 +1485,13 @@ public static T ChangeType<T>(object value)
         /// <param name="value">The value to convert</param>
         /// <param name="type">The type to convert the value to</param>
         /// <returns>The value converted to the requested type</returns>
-        public static object ChangeType(object value, Type type)
+        public static object ChangeType(object value, Type type, ExpressionExecutionContext context)
         {
             if (value != null && value.GetType() == type)
                 return value;
 
             var conversion = GetConversion(value.GetType(), type);
-            return conversion(value);
+            return conversion(value, context);
         }
 
         /// <summary>
@@ -1338,18 +1500,19 @@ public static object ChangeType(object value, Type type)
         /// <param name="sourceType">The type to convert from</param>
         /// <param name="destType">The type to convert to</param>
         /// <returns>A function that converts between the requested types</returns>
-        public static Func<object, object> GetConversion(Type sourceType, Type destType)
+        public static Func<object, ExpressionExecutionContext, object> GetConversion(Type sourceType, Type destType)
         {
             var key = sourceType.FullName + " -> " + destType.FullName;
             return _conversions.GetOrAdd(key, _ => CompileConversion(sourceType, destType));
         }
 
-        private static Func<object, object> CompileConversion(Type sourceType, Type destType)
+        private static Func<object, ExpressionExecutionContext, object> CompileConversion(Type sourceType, Type destType)
         {
             if (sourceType == destType)
-                return (object value) => value;
+                return (object value, ExpressionExecutionContext _) => value;
 
             var param = Expression.Parameter(typeof(object));
+            var contextParam = Expression.Parameter(typeof(ExpressionExecutionContext));
             var expression = (Expression) Expression.Convert(param, sourceType);
 
             // Special case for converting from string to enum for metadata filters
@@ -1408,14 +1571,14 @@ private static Func<object, object> CompileConversion(Type sourceType, Type dest
             }
             else
             {
-                expression = Convert(expression, destType);
+                expression = Convert(expression, contextParam, destType);
             }
 
             //if (destType == typeof(SqlString))
             //    expression = Expr.Call(() => ApplyCollation(Expr.Arg<ExpressionExecutionContext>(), Expr.Arg<SqlString>()), contextParam, expression);
 
             expression = Expression.Convert(expression, typeof(object));
-            return Expression.Lambda<Func<object,object>>(expression, param).Compile();
+            return Expression.Lambda<Func<object,ExpressionExecutionContext,object>>(expression, param, contextParam).Compile();
         }
 
         /// <summary>
@@ -1425,7 +1588,7 @@ private static Func<object, object> CompileConversion(Type sourceType, Type dest
         /// <param name="destType">The type to convert to</param>
         /// <param name="style">The style of the converesion</param>
         /// <returns>A function that converts between the requested types</returns>
-        public static Func<INullable, INullable> GetConversion(DataTypeReference sourceType, DataTypeReference destType, int? style = null)
+        public static Func<INullable, ExpressionExecutionContext, INullable> GetConversion(DataTypeReference sourceType, DataTypeReference destType, int? style = null)
         {
             var key = sourceType.ToSql() + " -> " + destType.ToSql();
 
@@ -1443,15 +1606,16 @@ public static Func<INullable, INullable> GetConversion(DataTypeReference sourceT
             return _sqlConversions.GetOrAdd(key, _ => CompileConversion(sourceType, destType, style));
         }
 
-        private static Func<INullable, INullable> CompileConversion(DataTypeReference sourceType, DataTypeReference destType, int? style = null)
+        private static Func<INullable, ExpressionExecutionContext, INullable> CompileConversion(DataTypeReference sourceType, DataTypeReference destType, int? style = null)
         {
             if (sourceType.IsSameAs(destType))
-                return (INullable value) => value;
+                return (INullable value, ExpressionExecutionContext _) => value;
 
             var sourceNetType = sourceType.ToNetType(out _);
             var destNetType = destType.ToNetType(out _);
 
             var param = Expression.Parameter(typeof(INullable));
+            var contextParam = Expression.Parameter(typeof(ExpressionExecutionContext));
             var expression = (Expression)Expression.Convert(param, sourceNetType);
             var styleExpr = (Expression)null;
             var styleType = (DataTypeReference)null;
@@ -1462,9 +1626,9 @@ private static Func<INullable, INullable> CompileConversion(DataTypeReference so
                 styleType = DataTypeHelpers.Int;
             }
 
-            expression = Convert(expression, sourceType, destType, styleExpr, styleType);
+            expression = Convert(expression, contextParam, sourceType, destType, styleExpr, styleType);
             expression = Expression.Convert(expression, typeof(INullable));
-            return Expression.Lambda<Func<INullable, INullable>>(expression, param).Compile();
+            return Expression.Lambda<Func<INullable, ExpressionExecutionContext, INullable>>(expression, param, contextParam).Compile();
         }
 
         /// <summary>
diff --git a/MarkMpn.Sql4Cds.Engine/ExecutionPlan/StreamAggregateNode.cs b/MarkMpn.Sql4Cds.Engine/ExecutionPlan/StreamAggregateNode.cs
index 3183d33e..1303b39b 100644
--- a/MarkMpn.Sql4Cds.Engine/ExecutionPlan/StreamAggregateNode.cs
+++ b/MarkMpn.Sql4Cds.Engine/ExecutionPlan/StreamAggregateNode.cs
@@ -77,7 +77,7 @@ protected override IEnumerable<Entity> ExecuteInternal(NodeExecutionContext cont
                 expressionExecutionContext.Entity = entity;
 
                 foreach (var func in states.Values)
-                    func.AggregateFunction.NextRecord(func.State);
+                    func.AggregateFunction.NextRecord(func.State, expressionExecutionContext);
             }
 
             if (states != null)
diff --git a/MarkMpn.Sql4Cds.Engine/ExecutionPlan/SystemFunctionNode.cs b/MarkMpn.Sql4Cds.Engine/ExecutionPlan/SystemFunctionNode.cs
index dac954ed..dbf48ed3 100644
--- a/MarkMpn.Sql4Cds.Engine/ExecutionPlan/SystemFunctionNode.cs
+++ b/MarkMpn.Sql4Cds.Engine/ExecutionPlan/SystemFunctionNode.cs
@@ -52,7 +52,7 @@ public override IDataExecutionPlanNodeInternal FoldQuery(NodeCompilationContext
 
         public override INodeSchema GetSchema(NodeCompilationContext context)
         {
-            var dataSource = context.DataSources[DataSource];
+            var dataSource = context.Session.DataSources[DataSource];
 
             switch (SystemFunction)
             {
@@ -97,7 +97,7 @@ protected override RowCountEstimate EstimateRowsOutInternal(NodeCompilationConte
 
         protected override IEnumerable<Entity> ExecuteInternal(NodeExecutionContext context)
         {
-            var dataSource = context.DataSources[DataSource];
+            var dataSource = context.Session.DataSources[DataSource];
 
             switch (SystemFunction)
             {
diff --git a/MarkMpn.Sql4Cds.Engine/ExecutionPlan/UpdateNode.cs b/MarkMpn.Sql4Cds.Engine/ExecutionPlan/UpdateNode.cs
index 3bf0dbe2..05916a35 100644
--- a/MarkMpn.Sql4Cds.Engine/ExecutionPlan/UpdateNode.cs
+++ b/MarkMpn.Sql4Cds.Engine/ExecutionPlan/UpdateNode.cs
@@ -98,7 +98,27 @@ public override IRootExecutionPlanNodeInternal[] FoldQuery(NodeCompilationContex
         {
             UseLegacyUpdateMessages = GetUseLegacyUpdateMessages(context, hints);
 
-            return base.FoldQuery(context, hints);
+            var result = base.FoldQuery(context, hints);
+
+            if (result.Length != 1 || result[0] != this)
+                return result;
+
+            // If we don't need to use any of the original values and we're filtering by ID we can bypass reading
+            // the record to update
+            if (ColumnMappings.Values.All(m => m.OldValueColumn == null))
+            {
+                var dataSource = context.Session.DataSources[DataSource];
+                var meta = dataSource.Metadata[LogicalName];
+
+                var requiredColumns = ColumnMappings
+                    .Select(kvp => kvp.Value.NewValueColumn)
+                    .Union(new[] { PrimaryIdSource })
+                    .ToArray();
+
+                FoldIdsToConstantScan(context, hints, LogicalName, requiredColumns);
+            }
+
+            return new[] { this };
         }
 
         private bool GetUseLegacyUpdateMessages(NodeCompilationContext context, IList<OptimizerHint> queryHints)
@@ -120,15 +140,16 @@ public override void Execute(NodeExecutionContext context, out int recordsAffect
 
             try
             {
-                if (!context.DataSources.TryGetValue(DataSource, out var dataSource))
+                if (!context.Session.DataSources.TryGetValue(DataSource, out var dataSource))
                     throw new QueryExecutionException("Missing datasource " + DataSource);
 
                 List<Entity> entities;
                 EntityMetadata meta;
                 Dictionary<string, AttributeMetadata> attributes;
-                Dictionary<string, Func<Entity, object>> newAttributeAccessors;
-                Dictionary<string, Func<Entity, object>> oldAttributeAccessors;
-                Func<Entity, object> primaryIdAccessor;
+                Dictionary<string, Func<ExpressionExecutionContext, object>> newAttributeAccessors;
+                Dictionary<string, Func<ExpressionExecutionContext, object>> oldAttributeAccessors;
+                Func<ExpressionExecutionContext, object> primaryIdAccessor;
+                var eec = new ExpressionExecutionContext(context);
 
                 using (_timer.Run())
                 {
@@ -213,8 +234,9 @@ public override void Execute(NodeExecutionContext context, out int recordsAffect
                         meta,
                         entity =>
                         {
-                            var preImage = ExtractEntity(entity, meta, attributes, oldAttributeAccessors, primaryIdAccessor);
-                            var update = ExtractEntity(entity, meta, attributes, newAttributeAccessors, primaryIdAccessor);
+                            eec.Entity = entity;
+                            var preImage = ExtractEntity(eec, meta, attributes, oldAttributeAccessors, primaryIdAccessor);
+                            var update = ExtractEntity(eec, meta, attributes, newAttributeAccessors, primaryIdAccessor);
 
                             var requests = new OrganizationRequestCollection();
 
@@ -568,9 +590,9 @@ private OptionSetValue GetDefaultStatusCode(EntityMetadata meta, int statecode)
             return new OptionSetValue((int)((StateOptionMetadata)stateCode).DefaultStatus);
         }
 
-        private Entity ExtractEntity(Entity entity, EntityMetadata meta, Dictionary<string, AttributeMetadata> attributes, Dictionary<string, Func<Entity, object>> newAttributeAccessors, Func<Entity, object> primaryIdAccessor)
+        private Entity ExtractEntity(ExpressionExecutionContext context, EntityMetadata meta, Dictionary<string, AttributeMetadata> attributes, Dictionary<string, Func<ExpressionExecutionContext, object>> newAttributeAccessors, Func<ExpressionExecutionContext, object> primaryIdAccessor)
         {
-            var update = new Entity(LogicalName, (Guid)primaryIdAccessor(entity));
+            var update = new Entity(LogicalName, (Guid)primaryIdAccessor(context));
             
             foreach (var attributeAccessor in newAttributeAccessors)
             {
@@ -582,14 +604,14 @@ private Entity ExtractEntity(Entity entity, EntityMetadata meta, Dictionary<stri
                 if (!String.IsNullOrEmpty(attr.AttributeOf))
                     continue;
 
-                var value = attributeAccessor.Value(entity);
+                var value = attributeAccessor.Value(context);
 
                 update[attr.LogicalName] = value;
             }
 
             // Special case for activitypointer - need to set the specific activity type code
             if (LogicalName == "activitypointer")
-                update.LogicalName = entity.GetAttributeValue<SqlString>(ColumnMappings["activitytypecode"].OldValueColumn).Value;
+                update.LogicalName = context.Entity.GetAttributeValue<SqlString>(ColumnMappings["activitytypecode"].OldValueColumn).Value;
 
             return update;
         }
diff --git a/MarkMpn.Sql4Cds.Engine/ExecutionPlanBuilder.cs b/MarkMpn.Sql4Cds.Engine/ExecutionPlanBuilder.cs
index bcb9b974..97c72d90 100644
--- a/MarkMpn.Sql4Cds.Engine/ExecutionPlanBuilder.cs
+++ b/MarkMpn.Sql4Cds.Engine/ExecutionPlanBuilder.cs
@@ -21,21 +21,21 @@ class ExecutionPlanBuilder
         private NodeCompilationContext _nodeContext;
         private Dictionary<string, AliasNode> _cteSubplans;
 
-        public ExecutionPlanBuilder(IEnumerable<DataSource> dataSources, IQueryExecutionOptions options)
+        public ExecutionPlanBuilder(SessionContext session, IQueryExecutionOptions options)
         {
-            DataSources = dataSources.ToDictionary(ds => ds.Name, StringComparer.OrdinalIgnoreCase);
+            Session = session;
             Options = options;
 
-            if (!DataSources.ContainsKey(Options.PrimaryDataSource))
+            if (!Session.DataSources.ContainsKey(Options.PrimaryDataSource))
                 throw new ArgumentOutOfRangeException(nameof(options), "Primary data source " + options.PrimaryDataSource + " not found");
 
             EstimatedPlanOnly = true;
         }
 
         /// <summary>
-        /// The connections that will be used by this conversion
+        /// The session that the query will be executed in
         /// </summary>
-        public IDictionary<string, DataSource> DataSources { get; }
+        public SessionContext Session { get; }
 
         /// <summary>
         /// Indicates how the query will be executed
@@ -52,7 +52,7 @@ public ExecutionPlanBuilder(IEnumerable<DataSource> dataSources, IQueryExecution
         /// </summary>
         public Action<Sql4CdsError> Log { get; set; }
 
-        private DataSource PrimaryDataSource => DataSources[Options.PrimaryDataSource];
+        private DataSource PrimaryDataSource => Session.DataSources[Options.PrimaryDataSource];
 
         /// <summary>
         /// Builds the execution plans for a SQL command
@@ -65,22 +65,19 @@ public IRootExecutionPlanNode[] Build(string sql, IDictionary<string, DataTypeRe
         {
             // Take a copy of the defined parameters so we can add more while we're building the query without
             // affecting the original collection until the query is actually run
-            var parameterTypes = new Dictionary<string, DataTypeReference>(StringComparer.OrdinalIgnoreCase);
-            _staticContext = new ExpressionCompilationContext(DataSources, Options, parameterTypes, null, null);
-            _nodeContext = new NodeCompilationContext(DataSources, Options, parameterTypes, Log);
+            var localParameterTypes = new Dictionary<string, DataTypeReference>(StringComparer.OrdinalIgnoreCase);
 
             if (parameters != null)
             {
                 foreach (var param in parameters)
-                    parameterTypes[param.Key] = param.Value;
+                    localParameterTypes[param.Key] = param.Value;
             }
 
             // Add in standard global variables
-            parameterTypes["@@IDENTITY"] = DataTypeHelpers.EntityReference;
-            parameterTypes["@@ROWCOUNT"] = DataTypeHelpers.Int;
-            parameterTypes["@@SERVERNAME"] = DataTypeHelpers.NVarChar(100, DataSources[Options.PrimaryDataSource].DefaultCollation, CollationLabel.CoercibleDefault);
-            parameterTypes["@@VERSION"] = DataTypeHelpers.NVarChar(Int32.MaxValue, DataSources[Options.PrimaryDataSource].DefaultCollation, CollationLabel.CoercibleDefault);
-            parameterTypes["@@ERROR"] = DataTypeHelpers.Int;
+            var parameterTypes = new LayeredDictionary<string, DataTypeReference>(Session.GlobalVariableTypes, localParameterTypes);
+
+            _staticContext = new ExpressionCompilationContext(Session, Options, parameterTypes, null, null);
+            _nodeContext = new NodeCompilationContext(Session, Options, parameterTypes, Log);
 
             var queries = new List<IRootExecutionPlanNodeInternal>();
 
@@ -96,11 +93,11 @@ public IRootExecutionPlanNode[] Build(string sql, IDictionary<string, DataTypeRe
             var hintValidator = new OptimizerHintValidatingVisitor(false);
             fragment.Accept(hintValidator);
 
-            if (hintValidator.TdsCompatible && TDSEndpoint.CanUseTDSEndpoint(Options, DataSources[Options.PrimaryDataSource].Connection))
+            if (hintValidator.TdsCompatible && TDSEndpoint.CanUseTDSEndpoint(Options, PrimaryDataSource.Connection))
             {
-                using (var con = DataSources[Options.PrimaryDataSource].Connection == null ? null : TDSEndpoint.Connect(DataSources[Options.PrimaryDataSource].Connection))
+                using (var con = PrimaryDataSource.Connection == null ? null : TDSEndpoint.Connect(PrimaryDataSource.Connection))
                 {
-                    var tdsEndpointCompatibilityVisitor = new TDSEndpointCompatibilityVisitor(con, DataSources[Options.PrimaryDataSource].Metadata);
+                    var tdsEndpointCompatibilityVisitor = new TDSEndpointCompatibilityVisitor(con, PrimaryDataSource.Metadata);
                     fragment.Accept(tdsEndpointCompatibilityVisitor);
 
                     if (tdsEndpointCompatibilityVisitor.IsCompatible && !tdsEndpointCompatibilityVisitor.RequiresCteRewrite)
@@ -130,7 +127,7 @@ public IRootExecutionPlanNode[] Build(string sql, IDictionary<string, DataTypeRe
             var script = (TSqlScript)fragment;
             script.Accept(new ReplacePrimaryFunctionsVisitor());
             script.Accept(new ExplicitCollationVisitor());
-            var optimizer = new ExecutionPlanOptimizer(DataSources, Options, parameterTypes, !EstimatedPlanOnly, _nodeContext.Log);
+            var optimizer = new ExecutionPlanOptimizer(Session, Options, parameterTypes, !EstimatedPlanOnly, _nodeContext.Log);
 
             // Convert each statement in turn to the appropriate query type
             foreach (var batch in script.Batches)
@@ -557,6 +554,8 @@ internal IRootExecutionPlanNodeInternal[] ConvertStatementInternal(TSqlStatement
                 plans = ConvertThrowStatement(@throw);
             else if (statement is RaiseErrorStatement raiserror)
                 plans = ConvertRaiseErrorStatement(raiserror);
+            else if (statement is SetCommandStatement setCommand)
+                plans = ConvertSetCommandStatement(setCommand);
             else
                 throw new NotSupportedQueryFragmentException(Sql4CdsError.NotSupported(statement, statement.GetType().Name.Replace("Statement", "").ToUpperInvariant()));
 
@@ -583,6 +582,27 @@ internal IRootExecutionPlanNodeInternal[] ConvertStatementInternal(TSqlStatement
             return output.ToArray();
         }
 
+        private IDmlQueryExecutionPlanNode[] ConvertSetCommandStatement(SetCommandStatement setCommand)
+        {
+            return setCommand.Commands
+                .Select(c => ConvertSetCommand(c))
+                .ToArray();
+        }
+
+        private IDmlQueryExecutionPlanNode ConvertSetCommand(SetCommand setCommand)
+        {
+            if (setCommand is GeneralSetCommand cmd)
+            {
+                switch (cmd.CommandType)
+                {
+                    case GeneralSetCommandType.DateFormat:
+                        return new SetDateFormatNode(cmd.Parameter);
+                }
+            }
+
+            throw new NotSupportedQueryFragmentException(Sql4CdsError.NotSupported(setCommand, setCommand.ToNormalizedSql()));
+        }
+
         private SelectNode ConvertRecursiveCTEQuery(QueryExpression queryExpression, INodeSchema anchorSchema, CteValidatorVisitor cteValidator, Dictionary<string, string> outerReferences)
         {
             // Convert the query using the anchor query as a subquery to check for ambiguous column names
@@ -1376,8 +1396,8 @@ private DataSource SelectDataSource(SchemaObjectName schemaObject)
         {
             var databaseName = schemaObject.DatabaseIdentifier?.Value ?? Options.PrimaryDataSource;
             
-            if (!DataSources.TryGetValue(databaseName, out var dataSource))
-                throw new NotSupportedQueryFragmentException(Sql4CdsError.InvalidObjectName(schemaObject)) { Suggestion = $"Available database names:\r\n* {String.Join("\r\n* ", DataSources.Keys.OrderBy(k => k))}" };
+            if (!Session.DataSources.TryGetValue(databaseName, out var dataSource))
+                throw new NotSupportedQueryFragmentException(Sql4CdsError.InvalidObjectName(schemaObject)) { Suggestion = $"Available database names:\r\n* {String.Join("\r\n* ", Session.DataSources.Keys.OrderBy(k => k))}" };
 
             return dataSource;
         }
@@ -1717,8 +1737,8 @@ private DeleteNode ConvertDeleteStatement(DeleteSpecification delete, IList<Opti
             if (deleteTarget.Ambiguous)
                 throw new NotSupportedQueryFragmentException(Sql4CdsError.AmbiguousTable(target));
 
-            if (!DataSources.TryGetValue(deleteTarget.TargetDataSource, out var dataSource))
-                throw new NotSupportedQueryFragmentException(Sql4CdsError.InvalidObjectName(target.SchemaObject)) { Suggestion = $"Available database names:\r\n* {String.Join("\r\n*", DataSources.Keys.OrderBy(k => k))}" };
+            if (!Session.DataSources.TryGetValue(deleteTarget.TargetDataSource, out var dataSource))
+                throw new NotSupportedQueryFragmentException(Sql4CdsError.InvalidObjectName(target.SchemaObject)) { Suggestion = $"Available database names:\r\n* {String.Join("\r\n*", Session.DataSources.Keys.OrderBy(k => k))}" };
 
             ValidateDMLSchema(deleteTarget.Target, true);
 
@@ -2061,8 +2081,8 @@ private UpdateNode ConvertUpdateStatement(UpdateSpecification update, IList<Opti
             if (updateTarget.Ambiguous)
                 throw new NotSupportedQueryFragmentException(Sql4CdsError.AmbiguousTable(target));
 
-            if (!DataSources.TryGetValue(updateTarget.TargetDataSource, out var dataSource))
-                throw new NotSupportedQueryFragmentException(Sql4CdsError.InvalidObjectName(target.SchemaObject)) { Suggestion = $"Available database names:\r\n* {String.Join("\r\n*", DataSources.Keys.OrderBy(k => k))}" };
+            if (!Session.DataSources.TryGetValue(updateTarget.TargetDataSource, out var dataSource))
+                throw new NotSupportedQueryFragmentException(Sql4CdsError.InvalidObjectName(target.SchemaObject)) { Suggestion = $"Available database names:\r\n* {String.Join("\r\n*", Session.DataSources.Keys.OrderBy(k => k))}" };
 
             ValidateDMLSchema(updateTarget.Target, false);
 
@@ -2607,11 +2627,11 @@ private UpdateNode ConvertSetClause(IList<SetClause> setClauses, HashSet<string>
 
         private IRootExecutionPlanNodeInternal ConvertSelectStatement(SelectStatement select)
         {
-            if (TDSEndpoint.CanUseTDSEndpoint(Options, DataSources[Options.PrimaryDataSource].Connection))
+            if (TDSEndpoint.CanUseTDSEndpoint(Options, PrimaryDataSource.Connection))
             {
-                using (var con = DataSources[Options.PrimaryDataSource].Connection == null ? null : TDSEndpoint.Connect(DataSources[Options.PrimaryDataSource].Connection))
+                using (var con = PrimaryDataSource.Connection == null ? null : TDSEndpoint.Connect(PrimaryDataSource.Connection))
                 {
-                    var tdsEndpointCompatibilityVisitor = new TDSEndpointCompatibilityVisitor(con, DataSources[Options.PrimaryDataSource].Metadata, false);
+                    var tdsEndpointCompatibilityVisitor = new TDSEndpointCompatibilityVisitor(con, PrimaryDataSource.Metadata, false);
                     select.Accept(tdsEndpointCompatibilityVisitor);
 
                     // Remove any custom optimizer hints
@@ -2627,7 +2647,8 @@ private IRootExecutionPlanNodeInternal ConvertSelectStatement(SelectStatement se
                         var sql = new SqlNode
                         {
                             DataSource = Options.PrimaryDataSource,
-                            Sql = select.ToSql()
+                            Sql = select.ToSql(),
+                            SelectStatement = select
                         };
 
                         var variables = new VariableCollectingVisitor();
@@ -3259,7 +3280,7 @@ private IDataExecutionPlanNodeInternal ConvertInSubquery(IDataExecutionPlanNodeI
                 else
                 {
                     // We need the inner list to be distinct to avoid creating duplicates during the join
-                    var innerSchema = innerQuery.Source.GetSchema(new NodeCompilationContext(DataSources, Options, parameters, Log));
+                    var innerSchema = innerQuery.Source.GetSchema(new NodeCompilationContext(Session, Options, parameters, Log));
                     if (innerQuery.ColumnSet[0].SourceColumn != innerSchema.PrimaryKey && !(innerQuery.Source is DistinctNode))
                     {
                         innerQuery.Source = new DistinctNode
@@ -3374,7 +3395,7 @@ private IDataExecutionPlanNodeInternal ConvertExistsSubquery(IDataExecutionPlanN
             var innerContext = new NodeCompilationContext(context, parameters);
             var references = new Dictionary<string, string>();
             var innerQuery = ConvertSelectStatement(existsSubquery.Subquery.QueryExpression, hints, schema, references, innerContext);
-            var innerSchema = innerQuery.Source.GetSchema(new NodeCompilationContext(DataSources, Options, parameters, Log));
+            var innerSchema = innerQuery.Source.GetSchema(new NodeCompilationContext(Session, Options, parameters, Log));
             var innerSchemaPrimaryKey = innerSchema.PrimaryKey;
 
             // Create the join
@@ -4494,8 +4515,8 @@ private bool UseMergeJoin(IDataExecutionPlanNodeInternal node, IDataExecutionPla
             if (outerKey == null)
                 return false;
 
-            var outerSchema = node.GetSchema(new NodeCompilationContext(DataSources, Options, null, Log));
-            var innerSchema = subNode.GetSchema(new NodeCompilationContext(DataSources, Options, null, Log));
+            var outerSchema = node.GetSchema(new NodeCompilationContext(Session, Options, null, Log));
+            var innerSchema = subNode.GetSchema(new NodeCompilationContext(Session, Options, null, Log));
 
             if (!outerSchema.ContainsColumn(outerKey, out outerKey) ||
                 !innerSchema.ContainsColumn(innerKey, out innerKey))
@@ -4568,7 +4589,7 @@ private bool UseMergeJoin(IDataExecutionPlanNodeInternal node, IDataExecutionPla
             if (semiJoin)
             {
                 // Regenerate the schema after changing the alias
-                innerSchema = subNode.GetSchema(new NodeCompilationContext(DataSources, Options, null, Log));
+                innerSchema = subNode.GetSchema(new NodeCompilationContext(Session, Options, null, Log));
 
                 if (innerSchema.PrimaryKey != rightAttribute.GetColumnName() && !(merge.RightSource is DistinctNode))
                 {
diff --git a/MarkMpn.Sql4Cds.Engine/ExecutionPlanOptimizer.cs b/MarkMpn.Sql4Cds.Engine/ExecutionPlanOptimizer.cs
index fe267e69..cc11571c 100644
--- a/MarkMpn.Sql4Cds.Engine/ExecutionPlanOptimizer.cs
+++ b/MarkMpn.Sql4Cds.Engine/ExecutionPlanOptimizer.cs
@@ -17,16 +17,16 @@ namespace MarkMpn.Sql4Cds.Engine
     /// </summary>
     class ExecutionPlanOptimizer
     {
-        public ExecutionPlanOptimizer(IDictionary<string, DataSource> dataSources, IQueryExecutionOptions options, IDictionary<string, DataTypeReference> parameterTypes, bool compileConditions, Action<Sql4CdsError> log)
+        public ExecutionPlanOptimizer(SessionContext session, IQueryExecutionOptions options, IDictionary<string, DataTypeReference> parameterTypes, bool compileConditions, Action<Sql4CdsError> log)
         {
-            DataSources = dataSources;
+            Session = session;
             Options = options;
             ParameterTypes = parameterTypes;
             CompileConditions = compileConditions;
             Log = log;
         }
 
-        public IDictionary<string, DataSource> DataSources { get; }
+        public SessionContext Session { get; }
 
         public IQueryExecutionOptions Options { get; }
 
@@ -52,7 +52,7 @@ public IRootExecutionPlanNodeInternal[] Optimize(IRootExecutionPlanNodeInternal
                 hints.Add(new ConditionalNode.DoNotCompileConditionsHint());
             }
 
-            var context = new NodeCompilationContext(DataSources, Options, ParameterTypes, Log);
+            var context = new NodeCompilationContext(Session, Options, ParameterTypes, Log);
 
             // Move any additional operators down to the FetchXml
             var bypassOptimization = hints != null && hints.OfType<UseHintList>().Any(list => list.Hints.Any(h => h.Value.Equals("DEBUG_BYPASS_OPTIMIZATION", StringComparison.OrdinalIgnoreCase)));
diff --git a/MarkMpn.Sql4Cds.Engine/ExpressionFunctions.cs b/MarkMpn.Sql4Cds.Engine/ExpressionFunctions.cs
index 44ffaf11..6f1841fa 100644
--- a/MarkMpn.Sql4Cds.Engine/ExpressionFunctions.cs
+++ b/MarkMpn.Sql4Cds.Engine/ExpressionFunctions.cs
@@ -1,7 +1,6 @@
 using MarkMpn.Sql4Cds.Engine.ExecutionPlan;
 using Microsoft.Crm.Sdk.Messages;
 using Microsoft.SqlServer.TransactSql.ScriptDom;
-using Microsoft.VisualBasic;
 using Microsoft.Xrm.Sdk;
 using System;
 using System.Collections.Generic;
@@ -194,17 +193,98 @@ public static SqlBoolean Json_Path_Exists(SqlString json, SqlString jpath)
         /// <returns>The modified date</returns>
         /// <see href="https://docs.microsoft.com/en-us/sql/t-sql/functions/dateadd-transact-sql?view=sql-server-ver15"/>
         [SqlFunction(IsDeterministic = true)]
-        public static SqlDateTime DateAdd(SqlString datepart, SqlDouble number, SqlDateTime date)
+        public static SqlDateTimeOffset DateAdd(SqlString datepart, SqlInt32 number, SqlDateTimeOffset date, [SourceType(nameof(date)), TargetType] DataTypeReference dateType)
         {
             if (number.IsNull || date.IsNull)
                 return SqlDateTime.Null;
 
-            var interval = DatePartToInterval(datepart.Value);
-            var value = DateAndTime.DateAdd(interval, number.Value, date.Value);
+            if (!TryParseDatePart(datepart.Value, out var interval))
+                throw new QueryExecutionException(Sql4CdsError.InvalidOptionValue(new StringLiteral { Value = datepart.Value }, "dateadd"));
 
-            // DateAdd loses the Kind property for some interval types - add it back in again
-            if (value.Kind == DateTimeKind.Unspecified)
-                value = DateTime.SpecifyKind(value, date.Value.Kind);
+            if (interval == Engine.DatePart.TZOffset)
+                throw new QueryExecutionException(Sql4CdsError.InvalidDatePart(null, datepart.Value, "dateadd", dateType));
+
+            DateTimeOffset value;
+
+            try
+            {
+                switch (interval)
+                {
+                    case Engine.DatePart.Year:
+                        value = date.Value.AddYears(number.Value);
+                        break;
+
+                    case Engine.DatePart.Quarter:
+                        value = date.Value.AddMonths(number.Value * 3);
+                        break;
+
+                    case Engine.DatePart.Month:
+                        value = date.Value.AddMonths(number.Value);
+                        break;
+
+                    case Engine.DatePart.DayOfYear:
+                    case Engine.DatePart.Day:
+                    case Engine.DatePart.WeekDay:
+                        value = date.Value.AddDays(number.Value);
+                        break;
+
+                    case Engine.DatePart.Week:
+                        value = date.Value.AddDays(number.Value * 7);
+                        break;
+
+                    case Engine.DatePart.Hour:
+                        value = date.Value.AddHours(number.Value);
+                        break;
+
+                    case Engine.DatePart.Minute:
+                        value = date.Value.AddMinutes(number.Value);
+                        break;
+
+                    case Engine.DatePart.Second:
+                        value = date.Value.AddSeconds(number.Value);
+                        break;
+
+                    case Engine.DatePart.Millisecond:
+                        value = date.Value.AddMilliseconds(number.Value);
+
+                        // https://learn.microsoft.com/en-us/sql/t-sql/functions/dateadd-transact-sql?view=sql-server-ver16#return-values-for-a-smalldatetime-date-and-a-second-or-fractional-seconds-datepart
+                        if (dateType.IsSameAs(DataTypeHelpers.SmallDateTime))
+                            value = value.AddMilliseconds(1);
+                        break;
+
+                    case Engine.DatePart.Microsecond:
+                        // Check data type & precision
+                        // https://learn.microsoft.com/en-us/sql/t-sql/functions/dateadd-transact-sql?view=sql-server-ver16#fractional-seconds-precision
+                        if (dateType.IsSameAs(DataTypeHelpers.SmallDateTime) || dateType.IsSameAs(DataTypeHelpers.DateTime) || dateType.IsSameAs(DataTypeHelpers.Date))
+                            throw new QueryExecutionException(Sql4CdsError.InvalidDatePart(null, datepart.Value, "dateadd", dateType));
+
+                        value = date.Value.AddTicks(number.Value * 10);
+                        break;
+
+                    case Engine.DatePart.Nanosecond:
+                        // Check data type & precision
+                        // https://learn.microsoft.com/en-us/sql/t-sql/functions/dateadd-transact-sql?view=sql-server-ver16#fractional-seconds-precision
+                        if (dateType.IsSameAs(DataTypeHelpers.SmallDateTime) || dateType.IsSameAs(DataTypeHelpers.DateTime) || dateType.IsSameAs(DataTypeHelpers.Date))
+                            throw new QueryExecutionException(Sql4CdsError.InvalidDatePart(null, datepart.Value, "dateadd", dateType));
+
+                        var ticks = (int)Math.Round(number.Value / 100M, MidpointRounding.AwayFromZero);
+                        value = date.Value.AddTicks(ticks);
+                        break;
+
+                    default:
+                        throw new QueryExecutionException(Sql4CdsError.InvalidOptionValue(new StringLiteral { Value = datepart.Value }, "datepart"));
+                }
+            }
+            catch (ArgumentOutOfRangeException)
+            {
+                throw new QueryExecutionException(Sql4CdsError.AdditionOverflow(null, dateType));
+            }
+
+            if (dateType.IsSameAs(DataTypeHelpers.SmallDateTime) && (value.DateTime < SqlSmallDateTime.MinValue.Value || value.DateTime > SqlSmallDateTime.MaxValue.Value))
+                throw new QueryExecutionException(Sql4CdsError.AdditionOverflow(null, dateType));
+
+            if (dateType.IsSameAs(DataTypeHelpers.DateTime) && (value.DateTime < SqlDateTime.MinValue.Value || value.DateTime > SqlDateTime.MaxValue.Value))
+                throw new QueryExecutionException(Sql4CdsError.AdditionOverflow(null, dateType));
 
             return value;
         }
@@ -218,13 +298,175 @@ public static SqlDateTime DateAdd(SqlString datepart, SqlDouble number, SqlDateT
         /// <returns>The number of whole <paramref name="datepart"/> units between <paramref name="startdate"/> and <paramref name="enddate"/></returns>
         /// <see href="https://docs.microsoft.com/en-us/sql/t-sql/functions/datediff-transact-sql?view=sql-server-ver15"/>
         [SqlFunction(IsDeterministic = true)]
-        public static SqlInt32 DateDiff(SqlString datepart, SqlDateTime startdate, SqlDateTime enddate)
+        public static SqlInt32 DateDiff(SqlString datepart, SqlDateTimeOffset startdate, SqlDateTimeOffset enddate, [SourceType(nameof(startdate))] DataTypeReference startdateType, [SourceType(nameof(enddate))] DataTypeReference enddateType)
         {
             if (startdate.IsNull || enddate.IsNull)
                 return SqlInt32.Null;
 
-            var interval = DatePartToInterval(datepart.Value);
-            return (int) DateAndTime.DateDiff(interval, startdate.Value, enddate.Value);
+            if (!TryParseDatePart(datepart.Value, out var interval))
+                throw new QueryExecutionException(Sql4CdsError.InvalidOptionValue(new StringLiteral { Value = datepart.Value }, "datediff"));
+
+            if (interval == Engine.DatePart.Nanosecond)
+                return 0;
+            else if (interval == Engine.DatePart.TZOffset)
+                throw new QueryExecutionException(Sql4CdsError.UnsupportedDatePart(null, datepart.Value, "datediff"));
+
+            if (interval == Engine.DatePart.WeekDay)
+            {
+                startdate = DateTrunc("day", startdate, startdateType);
+                enddate = DateTrunc("day", enddate, enddateType);
+            }
+            else
+            {
+                startdate = DateTrunc(datepart, startdate, startdateType);
+                enddate = DateTrunc(datepart, enddate, enddateType);
+            }
+
+            switch (interval)
+            {
+                case Engine.DatePart.Year:
+                    return enddate.Value.UtcDateTime.Year - startdate.Value.UtcDateTime.Year;
+
+                case Engine.DatePart.Quarter:
+                    var endQuarter = enddate.Value.UtcDateTime.Year * 4 + (enddate.Value.UtcDateTime.Month - 1) / 3 + 1;
+                    var startQuarter = startdate.Value.UtcDateTime.Year * 4 + (startdate.Value.UtcDateTime.Month - 1) / 3 + 1;
+                    return endQuarter - startQuarter;
+
+                case Engine.DatePart.Month:
+                    return (enddate.Value.UtcDateTime.Year - startdate.Value.UtcDateTime.Year) * 12 + enddate.Value.UtcDateTime.Month - startdate.Value.UtcDateTime.Month;
+
+                case Engine.DatePart.DayOfYear:
+                case Engine.DatePart.Day:
+                case Engine.DatePart.WeekDay:
+                    return (enddate.Value.UtcDateTime - startdate.Value.UtcDateTime).Days;
+
+                case Engine.DatePart.Week:
+                case Engine.DatePart.ISOWeek:
+                    return (enddate.Value.UtcDateTime - startdate.Value.UtcDateTime).Days / 7;
+
+                case Engine.DatePart.Hour:
+                    return (int)(enddate.Value.UtcDateTime - startdate.Value.UtcDateTime).TotalHours;
+
+                case Engine.DatePart.Minute:
+                    return (int)(enddate.Value.UtcDateTime - startdate.Value.UtcDateTime).TotalMinutes;
+
+                case Engine.DatePart.Second:
+                    return (int)(enddate.Value.UtcDateTime - startdate.Value.UtcDateTime).TotalSeconds;
+
+                case Engine.DatePart.Millisecond:
+                    return (int)(enddate.Value.UtcDateTime - startdate.Value.UtcDateTime).TotalMilliseconds;
+
+                case Engine.DatePart.Microsecond:
+                    return (int)((enddate.Value.UtcDateTime - startdate.Value.UtcDateTime).Ticks / 10);
+
+                case Engine.DatePart.Nanosecond:
+                    return (int)((enddate.Value.UtcDateTime - startdate.Value.UtcDateTime).Ticks * 100);
+
+                default:
+                    throw new QueryExecutionException(Sql4CdsError.InvalidOptionValue(new StringLiteral { Value = datepart.Value }, "datepart"));
+            }
+        }
+
+        /// <summary>
+        /// Implements the DATETRUNC function
+        /// </summary>
+        /// <param name="datepart">Specifies the precision for truncation</param>
+        /// <param name="date">The date value to be truncated</param>
+        /// <returns>The truncated version of the date</returns>
+        /// <see href="https://learn.microsoft.com/en-us/sql/t-sql/functions/datetrunc-transact-sql?view=sql-server-ver16"/>
+        [SqlFunction(IsDeterministic = true)]
+        public static SqlDateTimeOffset DateTrunc(SqlString datepart, SqlDateTimeOffset date, [SourceType(nameof(date)), TargetType] DataTypeReference dateType)
+        {
+            if (date.IsNull)
+                return SqlDateTimeOffset.Null;
+
+            if (!TryParseDatePart(datepart.Value, out var interval))
+                throw new QueryExecutionException(Sql4CdsError.InvalidOptionValue(new StringLiteral { Value = datepart.Value }, "datetrunc"));
+
+            if (interval == Engine.DatePart.WeekDay || interval == Engine.DatePart.TZOffset || interval == Engine.DatePart.Nanosecond)
+                throw new QueryExecutionException(Sql4CdsError.InvalidDatePart(null, datepart.Value, "datetrunc", dateType));
+
+            if (!(dateType is SqlDataTypeReference sqlDateType))
+                throw new QueryExecutionException(Sql4CdsError.InvalidDatePart(null, datepart.Value, "datetrunc", dateType));
+
+            var scale = dateType.GetScale();
+
+            switch (interval)
+            {
+                case Engine.DatePart.Year:
+                    if (sqlDateType.SqlDataTypeOption == SqlDataTypeOption.Time)
+                        throw new QueryExecutionException(Sql4CdsError.InvalidDatePart(null, datepart.Value, "datetrunc", dateType));
+
+                    return new DateTimeOffset(date.Value.Year, 1, 1, 0, 0, 0, date.Value.Offset);
+
+                case Engine.DatePart.Quarter:
+                    if (sqlDateType.SqlDataTypeOption == SqlDataTypeOption.Time)
+                        throw new QueryExecutionException(Sql4CdsError.InvalidDatePart(null, datepart.Value, "datetrunc", dateType));
+
+                    return new DateTimeOffset(date.Value.Year, (((date.Value.Month - 1) / 3) * 3) + 1, 1, 0, 0, 0, date.Value.Offset);
+
+                case Engine.DatePart.Month:
+                    if (sqlDateType.SqlDataTypeOption == SqlDataTypeOption.Time)
+                        throw new QueryExecutionException(Sql4CdsError.InvalidDatePart(null, datepart.Value, "datetrunc", dateType));
+
+                    return new DateTimeOffset(date.Value.Year, date.Value.Month, 1, 0, 0, 0, date.Value.Offset);
+
+                case Engine.DatePart.DayOfYear:
+                case Engine.DatePart.Day:
+                    if (sqlDateType.SqlDataTypeOption == SqlDataTypeOption.Time)
+                        throw new QueryExecutionException(Sql4CdsError.InvalidDatePart(null, datepart.Value, "datetrunc", dateType));
+
+                    return new DateTimeOffset(date.Value.Date, date.Value.Offset);
+
+                case Engine.DatePart.Week:
+                    if (sqlDateType.SqlDataTypeOption == SqlDataTypeOption.Time)
+                        throw new QueryExecutionException(Sql4CdsError.InvalidDatePart(null, datepart.Value, "datetrunc", dateType));
+
+                    return new DateTimeOffset(date.Value.Date, date.Value.Offset).AddDays(-(int)date.Value.DayOfWeek);
+
+                case Engine.DatePart.ISOWeek:
+                    if (sqlDateType.SqlDataTypeOption == SqlDataTypeOption.Time)
+                        throw new QueryExecutionException(Sql4CdsError.InvalidDatePart(null, datepart.Value, "datetrunc", dateType));
+
+                    var day = (int)date.Value.DayOfWeek;
+                    if (day == 0)
+                        day = 7;
+
+                    return new DateTimeOffset(date.Value.Date, date.Value.Offset).AddDays(-day + 1);
+
+                case Engine.DatePart.Hour:
+                    if (sqlDateType.SqlDataTypeOption == SqlDataTypeOption.Date)
+                        throw new QueryExecutionException(Sql4CdsError.InvalidDatePart(null, datepart.Value, "datetrunc", dateType));
+
+                    return new DateTimeOffset(date.Value.Year, date.Value.Month, date.Value.Day, date.Value.Hour, 0, 0, date.Value.Offset);
+
+                case Engine.DatePart.Minute:
+                    if (sqlDateType.SqlDataTypeOption == SqlDataTypeOption.Date)
+                        throw new QueryExecutionException(Sql4CdsError.InvalidDatePart(null, datepart.Value, "datetrunc", dateType));
+
+                    return new DateTimeOffset(date.Value.Year, date.Value.Month, date.Value.Day, date.Value.Hour, date.Value.Minute, 0, date.Value.Offset);
+
+                case Engine.DatePart.Second:
+                    if (sqlDateType.SqlDataTypeOption == SqlDataTypeOption.Date)
+                        throw new QueryExecutionException(Sql4CdsError.InvalidDatePart(null, datepart.Value, "datetrunc", dateType));
+
+                    return new DateTimeOffset(date.Value.Year, date.Value.Month, date.Value.Day, date.Value.Hour, date.Value.Minute, date.Value.Second, date.Value.Offset);
+
+                case Engine.DatePart.Millisecond:
+                    if (scale < 3)
+                        throw new QueryExecutionException(Sql4CdsError.InvalidDatePart(null, datepart.Value, "datetrunc", dateType));
+
+                    return new DateTimeOffset(date.Value.Year, date.Value.Month, date.Value.Day, date.Value.Hour, date.Value.Minute, date.Value.Second, date.Value.Millisecond, date.Value.Offset);
+
+                case Engine.DatePart.Microsecond:
+                    if (scale < 6)
+                        throw new QueryExecutionException(Sql4CdsError.InvalidDatePart(null, datepart.Value, "datetrunc", dateType));
+
+                    return date.Value.AddTicks(-date.Value.Ticks % 10);
+
+                default:
+                    throw new QueryExecutionException(Sql4CdsError.InvalidDatePart(null, datepart.Value, "datetrunc", dateType));
+            }
         }
 
         /// <summary>
@@ -234,75 +476,192 @@ public static SqlInt32 DateDiff(SqlString datepart, SqlDateTime startdate, SqlDa
         /// <param name="date">The date to extract the <paramref name="datepart"/> from</param>
         /// <returns>The <paramref name="datepart"/> of the <paramref name="date"/></returns>
         [SqlFunction(IsDeterministic = true)]
-        public static SqlInt32 DatePart(SqlString datepart, SqlDateTime date)
+        public static SqlInt32 DatePart(SqlString datepart, SqlDateTimeOffset date, [SourceType(nameof(date))] DataTypeReference dateType)
         {
             if (date.IsNull)
                 return SqlInt32.Null;
 
-            var interval = DatePartToInterval(datepart.Value);
-            return DateAndTime.DatePart(interval, date.Value);
+            if (!TryParseDatePart(datepart.Value, out var interval))
+                throw new QueryExecutionException(Sql4CdsError.InvalidOptionValue(new StringLiteral { Value = datepart.Value }, "datepart"));
+
+            var sqlDateType = dateType as SqlDataTypeReference;
+
+            switch (interval)
+            {
+                case Engine.DatePart.Year:
+                    if (sqlDateType?.SqlDataTypeOption == SqlDataTypeOption.Time)
+                        throw new QueryExecutionException(Sql4CdsError.InvalidDatePart(null, datepart.Value, "datepart", dateType));
+
+                    return date.Value.Year;
+
+                case Engine.DatePart.Quarter:
+                    if (sqlDateType?.SqlDataTypeOption == SqlDataTypeOption.Time)
+                        throw new QueryExecutionException(Sql4CdsError.InvalidDatePart(null, datepart.Value, "datepart", dateType));
+
+                    return (date.Value.Month - 1) / 3 + 1;
+
+                case Engine.DatePart.Month:
+                    if (sqlDateType?.SqlDataTypeOption == SqlDataTypeOption.Time)
+                        throw new QueryExecutionException(Sql4CdsError.InvalidDatePart(null, datepart.Value, "datepart", dateType));
+
+                    return date.Value.Month;
+
+                case Engine.DatePart.DayOfYear:
+                    if (sqlDateType?.SqlDataTypeOption == SqlDataTypeOption.Time)
+                        throw new QueryExecutionException(Sql4CdsError.InvalidDatePart(null, datepart.Value, "datepart", dateType));
+
+                    return date.Value.DayOfYear;
+
+                case Engine.DatePart.Day:
+                    if (sqlDateType?.SqlDataTypeOption == SqlDataTypeOption.Time)
+                        throw new QueryExecutionException(Sql4CdsError.InvalidDatePart(null, datepart.Value, "datepart", dateType));
+
+                    return date.Value.Day;
+
+                case Engine.DatePart.Week:
+                    if (sqlDateType?.SqlDataTypeOption == SqlDataTypeOption.Time)
+                        throw new QueryExecutionException(Sql4CdsError.InvalidDatePart(null, datepart.Value, "datepart", dateType));
+
+                    return CultureInfo.CurrentCulture.Calendar.GetWeekOfYear(date.Value.DateTime, CalendarWeekRule.FirstFourDayWeek, DayOfWeek.Sunday);
+
+                case Engine.DatePart.WeekDay:
+                    if (sqlDateType?.SqlDataTypeOption == SqlDataTypeOption.Time)
+                        throw new QueryExecutionException(Sql4CdsError.InvalidDatePart(null, datepart.Value, "datepart", dateType));
+
+                    return (int)date.Value.DayOfWeek + 1;
+
+                case Engine.DatePart.Hour:
+                    return date.Value.Hour;
+
+                case Engine.DatePart.Minute:
+                    return date.Value.Minute;
+
+                case Engine.DatePart.Second:
+                    return date.Value.Second;
+
+                case Engine.DatePart.Millisecond:
+                    return date.Value.Millisecond;
+
+                case Engine.DatePart.Microsecond:
+                    return (int)(date.Value.Ticks % 10_000_000) / 10;
+
+                case Engine.DatePart.Nanosecond:
+                    return (int)(date.Value.Ticks % 10_000_000) * 100;
+
+                case Engine.DatePart.TZOffset:
+                    if (sqlDateType?.SqlDataTypeOption != SqlDataTypeOption.DateTimeOffset && sqlDateType?.SqlDataTypeOption != SqlDataTypeOption.DateTime2 && sqlDateType?.SqlDataTypeOption.IsStringType() != true)
+                        throw new QueryExecutionException(Sql4CdsError.InvalidDatePart(null, datepart.Value, "datepart", dateType));
+
+                    return (int)date.Value.Offset.TotalMinutes;
+
+                case Engine.DatePart.ISOWeek:
+                    if (sqlDateType?.SqlDataTypeOption == SqlDataTypeOption.Time)
+                        throw new QueryExecutionException(Sql4CdsError.InvalidDatePart(null, datepart.Value, "datepart", dateType));
+
+                    return CultureInfo.CurrentCulture.Calendar.GetWeekOfYear(date.Value.DateTime, CalendarWeekRule.FirstFourDayWeek, DayOfWeek.Monday);
+
+                default:
+                    throw new QueryExecutionException(Sql4CdsError.InvalidOptionValue(new StringLiteral { Value = datepart.Value }, "datepart"));
+            }
         }
 
         /// <summary>
-        /// Converts the SQL datepart argument names to the equivalent enum values used by VisualBasic
+        /// Converts the SQL datepart argument names to the equivalent enum value
         /// </summary>
         /// <param name="datepart">The SQL name for the datepart argument</param>
-        /// <returns>The equivalent <see cref="DateInterval"/> value</returns>
-        internal static DateInterval DatePartToInterval(string datepart)
+        /// <returns>The equivalent <see cref="DatePart"/> value</returns>
+        internal static bool TryParseDatePart(string datepart, out DatePart parsed)
         {
             switch (datepart.ToLower())
             {
                 case "year":
                 case "yy":
                 case "yyyy":
-                    return DateInterval.Year;
+                    parsed = Engine.DatePart.Year;
+                    return true;
 
                 case "quarter":
                 case "qq":
                 case "q":
-                    return DateInterval.Quarter;
+                    parsed = Engine.DatePart.Quarter;
+                    return true;
 
                 case "month":
                 case "mm":
                 case "m":
-                    return DateInterval.Month;
+                    parsed = Engine.DatePart.Month;
+                    return true;
 
                 case "dayofyear":
                 case "dy":
                 case "y":
-                    return DateInterval.DayOfYear;
+                    parsed = Engine.DatePart.DayOfYear;
+                    return true;
 
                 case "day":
                 case "dd":
                 case "d":
-                    return DateInterval.Day;
-
-                case "weekday":
-                case "dw":
-                case "w":
-                    return DateInterval.Weekday;
+                    parsed = Engine.DatePart.Day;
+                    return true;
 
                 case "week":
                 case "wk":
                 case "ww":
-                    return DateInterval.WeekOfYear;
+                    parsed = Engine.DatePart.Week;
+                    return true;
+
+                case "weekday":
+                case "dw":
+                case "w": // Abbreviation is lised for DATEADD but not DATEPART
+                    parsed = Engine.DatePart.WeekDay;
+                    return true;
 
                 case "hour":
                 case "hh":
-                    return DateInterval.Hour;
+                    parsed = Engine.DatePart.Hour;
+                    return true;
 
                 case "minute":
-                case "mi":
+                case "mi": // Abbreviation is lised for DATEADD but not DATEPART
                 case "n":
-                    return DateInterval.Minute;
+                    parsed = Engine.DatePart.Minute;
+                    return true;
 
                 case "second":
                 case "ss":
                 case "s":
-                    return DateInterval.Second;
+                    parsed = Engine.DatePart.Second;
+                    return true;
+
+                case "millisecond":
+                case "ms":
+                    parsed = Engine.DatePart.Millisecond;
+                    return true;
+
+                case "microsecond":
+                case "mcs":
+                    parsed = Engine.DatePart.Microsecond;
+                    return true;
+
+                case "nanosecond":
+                case "ns":
+                    parsed = Engine.DatePart.Nanosecond;
+                    return true;
+
+                case "tzoffset":
+                case "tz":
+                    parsed = Engine.DatePart.TZOffset;
+                    return true;
+
+                case "iso_week":
+                case "isowk":
+                case "isoww":
+                    parsed = Engine.DatePart.ISOWeek;
+                    return true;
 
                 default:
-                    throw new ArgumentOutOfRangeException(nameof(datepart), $"Unsupported DATEPART value {datepart}");
+                    parsed = Engine.DatePart.Year;
+                    return false;
             }
         }
 
@@ -474,7 +833,7 @@ public static SqlInt32 Len(SqlString s)
         /// <param name="value">Any expression</param>
         /// <returns></returns>
         [SqlFunction(IsDeterministic = true)]
-        public static SqlInt32 DataLength<T>(T value, [SourceType] DataTypeReference type)
+        public static SqlInt32 DataLength<T>(T value, [SourceType(nameof(value))] DataTypeReference type)
             where T:INullable
         {
             if (value.IsNull)
@@ -731,7 +1090,7 @@ public static T IsNull<T>(T check, T replacement)
         /// <param name="culture">Optional argument specifying a culture</param>
         /// <returns></returns>
         [SqlFunction(IsDeterministic = false)]
-        public static SqlString Format<T>(T value, SqlString format, [Optional] SqlString culture, [SourceType] DataTypeReference type, ExpressionExecutionContext context)
+        public static SqlString Format<T>(T value, SqlString format, [Optional] SqlString culture, [SourceType(nameof(value))] DataTypeReference type, ExpressionExecutionContext context)
             where T : INullable
         {
             if (value.IsNull)
@@ -940,7 +1299,7 @@ public static object Value(SqlXml value, XPath2Expression query, [TargetType] Da
                 throw new QueryExecutionException(Sql4CdsError.NotSupported(null, $"XPath return type '{result.GetType().Name}'"));
 
             if (sqlValue.GetType() != targetNetType)
-                sqlValue = (INullable) SqlTypeConverter.ChangeType(sqlValue, targetNetType);
+                sqlValue = (INullable) SqlTypeConverter.ChangeType(sqlValue, targetNetType, context);
 
             return sqlValue;
         }
@@ -988,25 +1347,25 @@ public static SqlVariant ServerProperty(SqlString propertyName, ExpressionExecut
             switch (propertyName.Value.ToLowerInvariant())
             {
                 case "collation":
-                    return new SqlVariant(DataTypeHelpers.NVarChar(128, dataSource.DefaultCollation, CollationLabel.CoercibleDefault), dataSource.DefaultCollation.ToSqlString(dataSource.DefaultCollation.Name));
+                    return new SqlVariant(DataTypeHelpers.NVarChar(128, dataSource.DefaultCollation, CollationLabel.CoercibleDefault), dataSource.DefaultCollation.ToSqlString(dataSource.DefaultCollation.Name), context);
 
                 case "collationid":
-                    return new SqlVariant(DataTypeHelpers.Int, new SqlInt32(dataSource.DefaultCollation.LCID));
+                    return new SqlVariant(DataTypeHelpers.Int, new SqlInt32(dataSource.DefaultCollation.LCID), context);
 
                 case "comparisonstyle":
-                    return new SqlVariant(DataTypeHelpers.Int, new SqlInt32((int)dataSource.DefaultCollation.CompareOptions));
+                    return new SqlVariant(DataTypeHelpers.Int, new SqlInt32((int)dataSource.DefaultCollation.CompareOptions), context);
 
                 case "edition":
-                    return new SqlVariant(DataTypeHelpers.NVarChar(128, dataSource.DefaultCollation, CollationLabel.CoercibleDefault), dataSource.DefaultCollation.ToSqlString("Enterprise Edition"));
+                    return new SqlVariant(DataTypeHelpers.NVarChar(128, dataSource.DefaultCollation, CollationLabel.CoercibleDefault), dataSource.DefaultCollation.ToSqlString("Enterprise Edition"), context);
 
                 case "editionid":
-                    return new SqlVariant(DataTypeHelpers.BigInt, new SqlInt64(1804890536));
+                    return new SqlVariant(DataTypeHelpers.BigInt, new SqlInt64(1804890536), context);
 
                 case "enginedition":
-                    return new SqlVariant(DataTypeHelpers.Int, new SqlInt32(3));
+                    return new SqlVariant(DataTypeHelpers.Int, new SqlInt32(3), context);
 
                 case "issingleuser":
-                    return new SqlVariant(DataTypeHelpers.Int, new SqlInt32(0));
+                    return new SqlVariant(DataTypeHelpers.Int, new SqlInt32(0), context);
 
                 case "machinename":
                 case "servername":
@@ -1019,13 +1378,13 @@ public static SqlVariant ServerProperty(SqlString propertyName, ExpressionExecut
                     if (svc != null)
                         machineName = svc.CrmConnectOrgUriActual.Host;
 #endif
-                    return new SqlVariant(DataTypeHelpers.NVarChar(128, dataSource.DefaultCollation, CollationLabel.CoercibleDefault), dataSource.DefaultCollation.ToSqlString(machineName));
+                    return new SqlVariant(DataTypeHelpers.NVarChar(128, dataSource.DefaultCollation, CollationLabel.CoercibleDefault), dataSource.DefaultCollation.ToSqlString(machineName), context);
 
                 case "pathseparator":
-                    return new SqlVariant(DataTypeHelpers.NVarChar(1, dataSource.DefaultCollation, CollationLabel.CoercibleDefault), dataSource.DefaultCollation.ToSqlString(Path.DirectorySeparatorChar.ToString()));
+                    return new SqlVariant(DataTypeHelpers.NVarChar(1, dataSource.DefaultCollation, CollationLabel.CoercibleDefault), dataSource.DefaultCollation.ToSqlString(Path.DirectorySeparatorChar.ToString()), context);
 
                 case "processid":
-                    return new SqlVariant(DataTypeHelpers.Int, new SqlInt32(System.Diagnostics.Process.GetCurrentProcess().Id));
+                    return new SqlVariant(DataTypeHelpers.Int, new SqlInt32(System.Diagnostics.Process.GetCurrentProcess().Id), context);
 
                 case "productversion":
                     string orgVersion = null;
@@ -1041,14 +1400,14 @@ public static SqlVariant ServerProperty(SqlString propertyName, ExpressionExecut
                     if (orgVersion == null)
                         orgVersion = ((RetrieveVersionResponse)dataSource.Execute(new RetrieveVersionRequest())).Version;
 
-                    return new SqlVariant(DataTypeHelpers.NVarChar(128, dataSource.DefaultCollation, CollationLabel.CoercibleDefault), dataSource.DefaultCollation.ToSqlString(orgVersion));
+                    return new SqlVariant(DataTypeHelpers.NVarChar(128, dataSource.DefaultCollation, CollationLabel.CoercibleDefault), dataSource.DefaultCollation.ToSqlString(orgVersion), context);
             }
 
             return SqlVariant.Null;
         }
 
         [SqlFunction(IsDeterministic = false)]
-        public static SqlVariant Sql_Variant_Property(SqlVariant expression, SqlString property)
+        public static SqlVariant Sql_Variant_Property(SqlVariant expression, SqlString property, ExpressionExecutionContext context)
         {
             if (property.IsNull)
                 return SqlVariant.Null;
@@ -1057,42 +1416,42 @@ public static SqlVariant Sql_Variant_Property(SqlVariant expression, SqlString p
             {
                 case "basetype":
                     if (expression.BaseType == null)
-                        return new SqlVariant(DataTypeHelpers.NVarChar(128, Collation.USEnglish, CollationLabel.CoercibleDefault), SqlString.Null);
+                        return new SqlVariant(DataTypeHelpers.NVarChar(128, Collation.USEnglish, CollationLabel.CoercibleDefault), SqlString.Null, context);
 
                     if (expression.BaseType is SqlDataTypeReference sqlType)
-                        return new SqlVariant(DataTypeHelpers.NVarChar(128, Collation.USEnglish, CollationLabel.CoercibleDefault), Collation.USEnglish.ToSqlString(sqlType.SqlDataTypeOption.ToString().ToLowerInvariant()));
+                        return new SqlVariant(DataTypeHelpers.NVarChar(128, Collation.USEnglish, CollationLabel.CoercibleDefault), Collation.USEnglish.ToSqlString(sqlType.SqlDataTypeOption.ToString().ToLowerInvariant()), context);
 
-                    return new SqlVariant(DataTypeHelpers.NVarChar(128, Collation.USEnglish, CollationLabel.CoercibleDefault), Collation.USEnglish.ToSqlString(expression.BaseType.ToSql()));
+                    return new SqlVariant(DataTypeHelpers.NVarChar(128, Collation.USEnglish, CollationLabel.CoercibleDefault), Collation.USEnglish.ToSqlString(expression.BaseType.ToSql()), context);
 
                 case "precision":
                     if (expression.BaseType == null)
-                        return new SqlVariant(DataTypeHelpers.Int, SqlInt32.Null);
+                        return new SqlVariant(DataTypeHelpers.Int, SqlInt32.Null, context);
 
-                    return new SqlVariant(DataTypeHelpers.Int, new SqlInt32(expression.BaseType.GetPrecision()));
+                    return new SqlVariant(DataTypeHelpers.Int, new SqlInt32(expression.BaseType.GetPrecision()), context);
 
                 case "scale":
                     if (expression.BaseType == null)
-                        return new SqlVariant(DataTypeHelpers.Int, SqlInt32.Null);
+                        return new SqlVariant(DataTypeHelpers.Int, SqlInt32.Null, context);
 
-                    return new SqlVariant(DataTypeHelpers.Int, new SqlInt32(expression.BaseType.GetScale()));
+                    return new SqlVariant(DataTypeHelpers.Int, new SqlInt32(expression.BaseType.GetScale()), context);
 
                 case "totalbytes":
                     if (expression.BaseType == null)
-                        return new SqlVariant(DataTypeHelpers.Int, SqlInt32.Null);
+                        return new SqlVariant(DataTypeHelpers.Int, SqlInt32.Null, context);
 
-                    return new SqlVariant(DataTypeHelpers.Int, DataLength<INullable>(expression.Value, expression.BaseType));
+                    return new SqlVariant(DataTypeHelpers.Int, DataLength<INullable>(expression.Value, expression.BaseType), context);
 
                 case "collation":
                     if (!(expression.BaseType is SqlDataTypeReferenceWithCollation coll))
-                        return new SqlVariant(DataTypeHelpers.NVarChar(128, Collation.USEnglish, CollationLabel.CoercibleDefault), SqlString.Null);
+                        return new SqlVariant(DataTypeHelpers.NVarChar(128, Collation.USEnglish, CollationLabel.CoercibleDefault), SqlString.Null, context);
 
-                    return new SqlVariant(DataTypeHelpers.NVarChar(128, Collation.USEnglish, CollationLabel.CoercibleDefault), Collation.USEnglish.ToSqlString(coll.Collation.Name));
+                    return new SqlVariant(DataTypeHelpers.NVarChar(128, Collation.USEnglish, CollationLabel.CoercibleDefault), Collation.USEnglish.ToSqlString(coll.Collation.Name), context);
 
                 case "maxlength":
                     if (expression.BaseType == null)
-                        return new SqlVariant(DataTypeHelpers.Int, SqlInt32.Null);
+                        return new SqlVariant(DataTypeHelpers.Int, SqlInt32.Null, context);
 
-                    return new SqlVariant(DataTypeHelpers.Int, new SqlInt32(expression.BaseType.GetSize()));
+                    return new SqlVariant(DataTypeHelpers.Int, new SqlInt32(expression.BaseType.GetSize()), context);
             }
 
             return SqlVariant.Null;
@@ -1661,11 +2020,20 @@ class TargetTypeAttribute : Attribute
     }
 
     /// <summary>
-    /// Indicates that the parameter gives the type of the preceding parameter
+    /// Indicates that the parameter gives the orignal SQL type of another parameter
     /// </summary>
     [AttributeUsage(AttributeTargets.Parameter)]
     class SourceTypeAttribute : Attribute
     {
+        public SourceTypeAttribute(string sourceParameter)
+        {
+            SourceParameter = sourceParameter;
+        }
+
+        /// <summary>
+        /// Returns the name of the parameter this provides the original type of
+        /// </summary>
+        public string SourceParameter { get; }
     }
 
     /// <summary>
@@ -1683,4 +2051,26 @@ class OptionalAttribute : Attribute
     class CollationSensitiveAttribute : Attribute
     {
     }
+
+    /// <summary>
+    /// The available date parts for the DATEPART function
+    /// </summary>
+    enum DatePart
+    {
+        Year,
+        Quarter,
+        Month,
+        DayOfYear,
+        Day,
+        Week,
+        WeekDay,
+        Hour,
+        Minute,
+        Second,
+        Millisecond,
+        Microsecond,
+        Nanosecond,
+        TZOffset,
+        ISOWeek,
+    }
 }
diff --git a/MarkMpn.Sql4Cds.Engine/IQueryExecutionOptions.cs b/MarkMpn.Sql4Cds.Engine/IQueryExecutionOptions.cs
index 507d425c..ea1169f2 100644
--- a/MarkMpn.Sql4Cds.Engine/IQueryExecutionOptions.cs
+++ b/MarkMpn.Sql4Cds.Engine/IQueryExecutionOptions.cs
@@ -93,6 +93,11 @@ interface IQueryExecutionOptions
         /// </summary>
         string PrimaryDataSource { get; }
 
+        /// <summary>
+        /// An event that is fired when the <see cref="PrimaryDataSource"/> changes
+        /// </summary>
+        event EventHandler PrimaryDataSourceChanged;
+
         /// <summary>
         /// Returns the unique identifier of the current user
         /// </summary>
diff --git a/MarkMpn.Sql4Cds.Engine/LayeredDictionary.cs b/MarkMpn.Sql4Cds.Engine/LayeredDictionary.cs
new file mode 100644
index 00000000..3b952f73
--- /dev/null
+++ b/MarkMpn.Sql4Cds.Engine/LayeredDictionary.cs
@@ -0,0 +1,135 @@
+using System.Collections;
+using System.Collections.Generic;
+using System.Linq;
+
+namespace MarkMpn.Sql4Cds.Engine
+{
+    /// <summary>
+    /// A dictionary that combines multiple dictionaries into a single view
+    /// </summary>
+    /// <typeparam name="TKey"></typeparam>
+    /// <typeparam name="TValue"></typeparam>
+    class LayeredDictionary<TKey,TValue> : IDictionary<TKey,TValue>
+    {
+        private readonly IDictionary<TKey, TValue>[] _inner;
+        private readonly IDictionary<TKey, TValue> _fallback;
+
+        public LayeredDictionary(params IDictionary<TKey, TValue>[] inner)
+        {
+            _inner = inner;
+            _fallback = inner.Last();
+        }
+
+        public TValue this[TKey key]
+        {
+            get
+            {
+                foreach (var dict in _inner)
+                {
+                    if (dict.TryGetValue(key, out var value))
+                        return value;
+                }
+
+                throw new KeyNotFoundException();
+            }
+            set
+            {
+                foreach (var dict in _inner)
+                {
+                    if (dict == _fallback || dict.ContainsKey(key))
+                    {
+                        dict[key] = value;
+                        return;
+                    }
+                }
+            }
+        }
+
+        public ICollection<TKey> Keys => _inner.SelectMany(d => d.Keys).ToArray();
+
+        public ICollection<TValue> Values => _inner.SelectMany(d => d.Values).ToArray();
+
+        public int Count => _inner.Sum(d => d.Count);
+
+        public bool IsReadOnly => _inner.Any(d => d.IsReadOnly);
+
+        public void Add(TKey key, TValue value)
+        {
+            _fallback.Add(key, value);
+        }
+
+        public void Add(KeyValuePair<TKey, TValue> item)
+        {
+            _fallback.Add(item);
+        }
+
+        public void Clear()
+        {
+            foreach (var dict in _inner)
+                dict.Clear();
+        }
+
+        public bool Contains(KeyValuePair<TKey, TValue> item)
+        {
+            return _inner.Any(d => d.Contains(item));
+        }
+
+        public bool ContainsKey(TKey key)
+        {
+            return _inner.Any(d => d.ContainsKey(key));
+        }
+
+        public void CopyTo(KeyValuePair<TKey, TValue>[] array, int arrayIndex)
+        {
+            foreach (var dict in _inner)
+            {
+                dict.CopyTo(array, arrayIndex);
+                arrayIndex += dict.Count;
+            }
+        }
+
+        public IEnumerator<KeyValuePair<TKey, TValue>> GetEnumerator()
+        {
+            return _inner.SelectMany(d => d).GetEnumerator();
+        }
+
+        public bool Remove(TKey key)
+        {
+            foreach (var dict in _inner)
+            {
+                if (dict.Remove(key))
+                    return true;
+            }
+
+            return false;
+        }
+
+        public bool Remove(KeyValuePair<TKey, TValue> item)
+        {
+            foreach (var dict in _inner)
+            {
+                if (dict.Remove(item))
+                    return true;
+            }
+
+            return false;
+        }
+
+        public bool TryGetValue(TKey key, out TValue value)
+        {
+            foreach (var dict in _inner)
+            {
+                if (dict.TryGetValue(key, out value))
+                    return true;
+            }
+
+            value = default;
+            return false;
+        }
+
+        IEnumerator IEnumerable.GetEnumerator()
+        {
+            return GetEnumerator();
+        }
+    }
+}
diff --git a/MarkMpn.Sql4Cds.Engine/MarkMpn.Sql4Cds.Engine.csproj b/MarkMpn.Sql4Cds.Engine/MarkMpn.Sql4Cds.Engine.csproj
index 73e366a1..fb51d2ca 100644
--- a/MarkMpn.Sql4Cds.Engine/MarkMpn.Sql4Cds.Engine.csproj
+++ b/MarkMpn.Sql4Cds.Engine/MarkMpn.Sql4Cds.Engine.csproj
@@ -36,7 +36,6 @@
     <PackageReference Include="Microsoft.SqlServer.TransactSql.ScriptDom" Version="161.8834.0" />
     <PackageReference Include="System.Data.SqlClient" Version="4.8.6" />
     <PackageReference Include="XPath2.Extensions" Version="1.1.3" />
-    <Reference Include="Microsoft.VisualBasic" Condition=" '$(TargetFramework)' == 'net462' " />
   </ItemGroup>
 
   <Target Name="PostBuild" AfterTargets="PostBuildEvent" Condition=" '$(Configuration)|$(Platform)' == 'Debug|AnyCPU' And '$(TargetFramework)' == 'net462' ">
diff --git a/MarkMpn.Sql4Cds.Engine/MetaMetadataCache.cs b/MarkMpn.Sql4Cds.Engine/MetaMetadataCache.cs
index 6ae8895b..27dbdafd 100644
--- a/MarkMpn.Sql4Cds.Engine/MetaMetadataCache.cs
+++ b/MarkMpn.Sql4Cds.Engine/MetaMetadataCache.cs
@@ -46,6 +46,8 @@ class StubOptions : IQueryExecutionOptions
 
             public string PrimaryDataSource => throw new NotImplementedException();
 
+            public event EventHandler PrimaryDataSourceChanged;
+
             public Guid UserId => throw new NotImplementedException();
 
             public bool QuotedIdentifiers => throw new NotImplementedException();
diff --git a/MarkMpn.Sql4Cds.Engine/MetadataExtensions.cs b/MarkMpn.Sql4Cds.Engine/MetadataExtensions.cs
index 83858604..984294d6 100644
--- a/MarkMpn.Sql4Cds.Engine/MetadataExtensions.cs
+++ b/MarkMpn.Sql4Cds.Engine/MetadataExtensions.cs
@@ -5,6 +5,7 @@
 using System.Linq;
 using System.Text;
 using System.Threading.Tasks;
+using MarkMpn.Sql4Cds.Engine.ExecutionPlan;
 using Microsoft.SqlServer.TransactSql.ScriptDom;
 using Microsoft.Xrm.Sdk;
 using Microsoft.Xrm.Sdk.Metadata;
@@ -251,6 +252,52 @@ public static DataTypeReference GetAttributeSqlType(this AttributeMetadata attrM
 
             throw new ApplicationException("Unknown attribute type " + attrMetadata.GetType());
         }
+
+        /// <summary>
+        /// Converts a constant string value to an expression that generates the value of the appropriate type for use in a DML operation
+        /// </summary>
+        /// <param name="attribute">The attribute to convert the value for</param>
+        /// <param name="value">The string representation of the value</param>
+        /// <param name="isVariable">Indicates if the value is a variable name</param>
+        /// <param name="context">The context that the expression is being compiled in</param>
+        /// <param name="dataSource">The data source that the operation will be performed in</param>
+        /// <returns>An expression that returns the value in the appropriate type</returns>
+        internal static ScalarExpression GetDmlValue(this AttributeMetadata attribute, string value, bool isVariable, ExpressionCompilationContext context, DataSource dataSource)
+        {
+            var expr = (ScalarExpression)new StringLiteral { Value = value };
+
+            if (isVariable)
+                expr = new VariableReference { Name = value };
+
+            expr.GetType(context, out var exprType);
+            var attrType = attribute.GetAttributeSqlType(dataSource, false);
+
+            if (DataTypeHelpers.IsSameAs(exprType, attrType))
+                return expr;
+
+            if (attribute.IsPrimaryId == true)
+            {
+                expr = new FunctionCall
+                {
+                    FunctionName = new Identifier { Value = nameof(ExpressionFunctions.CreateLookup) },
+                    Parameters =
+                    {
+                        new StringLiteral { Value = attribute.EntityLogicalName },
+                        expr
+                    }
+                };
+            }
+            else
+            {
+                expr = new CastCall
+                {
+                    Parameter = expr,
+                    DataType = attrType
+                };
+            }
+
+            return expr;
+        }
     }
 
     /// <summary>
diff --git a/MarkMpn.Sql4Cds.Engine/NodeContext.cs b/MarkMpn.Sql4Cds.Engine/NodeContext.cs
index 01d16b73..27f792b1 100644
--- a/MarkMpn.Sql4Cds.Engine/NodeContext.cs
+++ b/MarkMpn.Sql4Cds.Engine/NodeContext.cs
@@ -24,12 +24,12 @@ class NodeCompilationContext
         /// <param name="parameterTypes">The names and types of the parameters that are available to the query</param>
         /// <param name="log">A callback function to log messages</param>
         public NodeCompilationContext(
-            IDictionary<string, DataSource> dataSources,
+            SessionContext session,
             IQueryExecutionOptions options,
             IDictionary<string, DataTypeReference> parameterTypes,
             Action<Sql4CdsError> log)
         {
-            DataSources = dataSources;
+            Session = session;
             Options = options;
             ParameterTypes = parameterTypes;
             GlobalCalculations = new NestedLoopNode
@@ -58,7 +58,7 @@ public NodeCompilationContext(
             NodeCompilationContext parentContext,
             IDictionary<string, DataTypeReference> parameterTypes)
         {
-            DataSources = parentContext.DataSources;
+            Session = parentContext.Session;
             Options = parentContext.Options;
             ParameterTypes = parameterTypes;
             GlobalCalculations = parentContext.GlobalCalculations;
@@ -67,9 +67,9 @@ public NodeCompilationContext(
         }
 
         /// <summary>
-        /// Returns the data sources that are available to the query
+        /// Returns the connection session the query will be executed in
         /// </summary>
-        public IDictionary<string, DataSource> DataSources { get; }
+        public SessionContext Session { get; }
 
         /// <summary>
         /// Returns the options that the query will be executed with
@@ -84,7 +84,7 @@ public NodeCompilationContext(
         /// <summary>
         /// Returns the details of the primary data source
         /// </summary>
-        public DataSource PrimaryDataSource => DataSources[Options.PrimaryDataSource];
+        public DataSource PrimaryDataSource => Session.DataSources[Options.PrimaryDataSource];
 
         /// <summary>
         /// Returns a <see cref="NestedLoopNode"/> which can be used to calculate global values to be injected into other nodes
@@ -142,12 +142,40 @@ class NodeExecutionContext : NodeCompilationContext
         /// <param name="parameterValues">The current value of each parameter</param>
         /// <param name="log">A callback function to log messages</param>
         public NodeExecutionContext(
-            IDictionary<string, DataSource> dataSources,
+            SessionContext session,
             IQueryExecutionOptions options,
             IDictionary<string, DataTypeReference> parameterTypes,
             IDictionary<string, INullable> parameterValues,
             Action<Sql4CdsError> log)
-            : base(dataSources, options, parameterTypes, log)
+            : base(session, options, parameterTypes, log)
+        {
+            ParameterValues = parameterValues;
+        }
+
+        /// <summary>
+        /// Creates a new <see cref="NodeExecutionContext"/> based on a <see cref="NodeCompilationContext"/>
+        /// </summary>
+        /// <param name="parentContext">The <see cref="NodeCompilationContext"/> to inherit settings from</param>
+        /// <param name="parameterValues">The values to use for any parameters</param>
+        public NodeExecutionContext(
+            NodeCompilationContext parentContext,
+            IDictionary<string, INullable> parameterValues)
+            : base(parentContext, parentContext.ParameterTypes)
+        {
+            ParameterValues = parameterValues;
+        }
+
+        /// <summary>
+        /// Creates a new <see cref="NodeExecutionContext"/> based on another context but with additional parameters for a subquery
+        /// </summary>
+        /// <param name="parentContext">The <see cref="NodeExecutionContext"/> to inherit settings from</param>
+        /// <param name="parameterTypes">The names and types of the parameters that are available to the subquery</param>
+        /// <param name="parameterValues">The current value of each parameter</param>
+        public NodeExecutionContext(
+            NodeExecutionContext parentContext,
+            IDictionary<string, DataTypeReference> parameterTypes,
+            IDictionary<string, INullable> parameterValues)
+            : base(parentContext, parameterTypes)
         {
             ParameterValues = parameterValues;
         }
@@ -157,6 +185,9 @@ public NodeExecutionContext(
         /// </summary>
         public IDictionary<string, INullable> ParameterValues { get; }
 
+        /// <summary>
+        /// Returns or sets the current error
+        /// </summary>
         public Sql4CdsError Error { get; set; }
     }
 
@@ -174,12 +205,12 @@ class ExpressionCompilationContext : NodeCompilationContext
         /// <param name="schema">The schema of data which is available to the expression</param>
         /// <param name="nonAggregateSchema">The schema of data prior to aggregation</param>
         public ExpressionCompilationContext(
-            IDictionary<string, DataSource> dataSources,
+            SessionContext session,
             IQueryExecutionOptions options,
             IDictionary<string, DataTypeReference> parameterTypes,
             INodeSchema schema,
             INodeSchema nonAggregateSchema)
-            : base(dataSources, options, parameterTypes, null)
+            : base(session, options, parameterTypes, null)
         {
             Schema = schema;
             NonAggregateSchema = nonAggregateSchema;
@@ -195,7 +226,7 @@ public ExpressionCompilationContext(
             NodeCompilationContext nodeContext,
             INodeSchema schema,
             INodeSchema nonAggregateSchema)
-            : base(nodeContext.DataSources, nodeContext.Options, nodeContext.ParameterTypes, nodeContext.Log)
+            : base(nodeContext.Session, nodeContext.Options, nodeContext.ParameterTypes, nodeContext.Log)
         {
             Schema = schema;
             NonAggregateSchema = nonAggregateSchema;
@@ -228,13 +259,13 @@ class ExpressionExecutionContext : NodeExecutionContext
         /// <param name="entity">The values for the current row the expression is being evaluated for</param>
         /// <param name="parameterValues">The current value of each parameter</param>
         public ExpressionExecutionContext(
-            IDictionary<string, DataSource> dataSources,
+            SessionContext session,
             IQueryExecutionOptions options,
             IDictionary<string, DataTypeReference> parameterTypes,
             IDictionary<string, INullable> parameterValues,
             Action<Sql4CdsError> log,
             Entity entity)
-            : base(dataSources, options, parameterTypes, parameterValues, log)
+            : base(session, options, parameterTypes, parameterValues, log)
         {
             Entity = entity;
         }
@@ -249,7 +280,7 @@ public ExpressionExecutionContext(
         /// representing each row as it is processed.
         /// </remarks>
         public ExpressionExecutionContext(NodeExecutionContext nodeContext)
-            : base(nodeContext.DataSources, nodeContext.Options, nodeContext.ParameterTypes, nodeContext.ParameterValues, nodeContext.Log)
+            : base(nodeContext, nodeContext.ParameterValues)
         {
             Entity = null;
             Error = nodeContext.Error;
@@ -268,7 +299,7 @@ public ExpressionExecutionContext(NodeExecutionContext nodeContext)
         /// representing each row as it is processed.
         /// </remarks>
         public ExpressionExecutionContext(ExpressionCompilationContext compilationContext)
-            : base(compilationContext.DataSources, compilationContext.Options, compilationContext.ParameterTypes, null, null)
+            : base(compilationContext, null)
         {
             Entity = null;
         }
diff --git a/MarkMpn.Sql4Cds.Engine/SessionContext.cs b/MarkMpn.Sql4Cds.Engine/SessionContext.cs
new file mode 100644
index 00000000..d8dda573
--- /dev/null
+++ b/MarkMpn.Sql4Cds.Engine/SessionContext.cs
@@ -0,0 +1,233 @@
+using System;
+using System.Collections;
+using System.Collections.Generic;
+using System.Data.SqlTypes;
+using System.Linq;
+using System.Reflection;
+using System.Text;
+using System.Threading.Tasks;
+using Microsoft.Crm.Sdk.Messages;
+using Microsoft.SqlServer.TransactSql.ScriptDom;
+#if NETCOREAPP
+using Microsoft.PowerPlatform.Dataverse.Client;
+#else
+using Microsoft.Xrm.Tooling.Connector;
+#endif
+
+namespace MarkMpn.Sql4Cds.Engine
+{
+    /// <summary>
+    /// Holds context for a session that should be persisted across multiple queries
+    /// </summary>
+    class SessionContext
+    {
+        /// <summary>
+        /// Provides just-in-time access to global variables that require a service request to determine the value for
+        /// </summary>
+        class SessionContextVariables : IDictionary<string, INullable>
+        {
+            private readonly SessionContext _context;
+            private readonly Dictionary<string, Lazy<INullable>> _values;
+
+            public SessionContextVariables(SessionContext context)
+            {
+                _context = context;
+                _values = new Dictionary<string, Lazy<INullable>>(StringComparer.OrdinalIgnoreCase);
+                Reset();
+            }
+
+            public void Reset()
+            {
+                _values["@@SERVERNAME"] = new Lazy<INullable>(() => GetServerName());
+                _values["@@VERSION"] = new Lazy<INullable>(() => GetVersion());
+            }
+
+            private SqlString GetVersion()
+            {
+                var dataSource = _context.DataSources[_context._options.PrimaryDataSource];
+                string orgVersion = null;
+
+#if NETCOREAPP
+                if (dataSource.Connection is ServiceClient svc)
+                    orgVersion = svc.ConnectedOrgVersion.ToString();
+#else
+                if (dataSource.Connection is CrmServiceClient svc)
+                    orgVersion = svc.ConnectedOrgVersion.ToString();
+#endif
+
+                if (orgVersion == null)
+                    orgVersion = ((RetrieveVersionResponse)dataSource.Execute(new RetrieveVersionRequest())).Version;
+
+                var assembly = typeof(Sql4CdsConnection).Assembly;
+                var assemblyVersion = assembly.GetName().Version;
+                var assemblyCopyright = assembly
+                    .GetCustomAttributes(typeof(AssemblyCopyrightAttribute), false)
+                    .OfType<AssemblyCopyrightAttribute>()
+                    .FirstOrDefault()?
+                    .Copyright;
+                var assemblyFilename = assembly.Location;
+                var assemblyDate = System.IO.File.GetLastWriteTime(assemblyFilename);
+
+                return $"Microsoft Dataverse - {orgVersion}\r\n\tSQL 4 CDS - {assemblyVersion}\r\n\t{assemblyDate:MMM dd yyyy HH:mm:ss}\r\n\t{assemblyCopyright}";
+            }
+
+            private SqlString GetServerName()
+            {
+                var dataSource = _context.DataSources[_context._options.PrimaryDataSource];
+
+#if NETCOREAPP
+                var svc = dataSource.Connection as ServiceClient;
+
+                if (svc != null)
+                    return svc.ConnectedOrgUriActual.Host;
+#else
+                var svc = dataSource.Connection as CrmServiceClient;
+
+                if (svc != null)
+                    return svc.CrmConnectOrgUriActual.Host;
+#endif
+
+                return dataSource.Name;
+            }
+
+            public INullable this[string key]
+            {
+                get => _values[key].Value;
+                set => throw new NotImplementedException();
+            }
+
+            public ICollection<string> Keys => _values.Keys;
+
+            public ICollection<INullable> Values => _values.Values.Select(v => v.Value).ToArray();
+
+            public int Count => _values.Count;
+
+            public bool IsReadOnly => true;
+
+            public void Add(string key, INullable value)
+            {
+                throw new NotImplementedException();
+            }
+
+            public void Add(KeyValuePair<string, INullable> item)
+            {
+                throw new NotImplementedException();
+            }
+
+            public void Clear()
+            {
+                throw new NotImplementedException();
+            }
+
+            public bool Contains(KeyValuePair<string, INullable> item)
+            {
+                return _values.TryGetValue(item.Key, out var val)
+                    && val.Value.Equals(item.Value);
+            }
+
+            public bool ContainsKey(string key)
+            {
+                return _values.ContainsKey(key);
+            }
+
+            public void CopyTo(KeyValuePair<string, INullable>[] array, int arrayIndex)
+            {
+                foreach (var item in this)
+                {
+                    array[arrayIndex] = item;
+                    arrayIndex++;
+                }
+            }
+
+            public IEnumerator<KeyValuePair<string, INullable>> GetEnumerator()
+            {
+                foreach (var item in _values)
+                    yield return new KeyValuePair<string, INullable>(item.Key, item.Value.Value);
+            }
+
+            public bool Remove(string key)
+            {
+                throw new NotImplementedException();
+            }
+
+            public bool Remove(KeyValuePair<string, INullable> item)
+            {
+                throw new NotImplementedException();
+            }
+
+            public bool TryGetValue(string key, out INullable value)
+            {
+                if (!_values.TryGetValue(key, out var lazy))
+                {
+                    value = default;
+                    return false;
+                }
+
+                value = lazy.Value;
+                return true;
+            }
+
+            IEnumerator IEnumerable.GetEnumerator()
+            {
+                return GetEnumerator();
+            }
+        }
+
+        private readonly IQueryExecutionOptions _options;
+        private readonly SessionContextVariables _variables;
+
+        public SessionContext(IDictionary<string, DataSource> dataSources, IQueryExecutionOptions options)
+        {
+            _options = options;
+            DataSources = dataSources;
+            DateFormat = DateFormat.mdy;
+            _variables = new SessionContextVariables(this);
+
+            GlobalVariableTypes = new Dictionary<string, DataTypeReference>(StringComparer.OrdinalIgnoreCase)
+            {
+                ["@@IDENTITY"] = DataTypeHelpers.EntityReference,
+                ["@@ROWCOUNT"] = DataTypeHelpers.Int,
+                ["@@ERROR"] = DataTypeHelpers.Int,
+            };
+
+            GlobalVariableValues = new LayeredDictionary<string, INullable>(
+                new Dictionary<string, INullable>(StringComparer.OrdinalIgnoreCase)
+                {
+                    ["@@IDENTITY"] = SqlEntityReference.Null,
+                    ["@@ROWCOUNT"] = (SqlInt32)0,
+                    ["@@ERROR"] = (SqlInt32)0,
+                },
+                _variables);
+
+            GetServerDetails();
+            _options.PrimaryDataSourceChanged += (_, __) => GetServerDetails();
+        }
+
+        private void GetServerDetails()
+        {
+            GlobalVariableTypes["@@SERVERNAME"] = DataTypeHelpers.NVarChar(100, DataSources[_options.PrimaryDataSource].DefaultCollation, CollationLabel.CoercibleDefault);
+            GlobalVariableTypes["@@VERSION"] = DataTypeHelpers.NVarChar(Int32.MaxValue, DataSources[_options.PrimaryDataSource].DefaultCollation, CollationLabel.CoercibleDefault);
+            _variables.Reset();
+        }
+
+        /// <summary>
+        /// Returns the data sources that are available to the query
+        /// </summary>
+        public IDictionary<string, DataSource> DataSources { get; }
+
+        /// <summary>
+        /// Returns or sets the current SET DATEFORMAT option
+        /// </summary>
+        public DateFormat DateFormat { get; set; }
+
+        /// <summary>
+        /// Returns the types of the global variables
+        /// </summary>
+        internal Dictionary<string, DataTypeReference> GlobalVariableTypes { get; }
+
+        /// <summary>
+        /// Returns the values of the global variables
+        /// </summary>
+        internal IDictionary<string, INullable> GlobalVariableValues { get; }
+    }
+}
diff --git a/MarkMpn.Sql4Cds.Engine/SqlDateTypes.cs b/MarkMpn.Sql4Cds.Engine/SqlDateTypes.cs
index e37fe40c..3058b8a2 100644
--- a/MarkMpn.Sql4Cds.Engine/SqlDateTypes.cs
+++ b/MarkMpn.Sql4Cds.Engine/SqlDateTypes.cs
@@ -1,300 +1,600 @@
 using System;
 using System.Collections.Generic;
 using System.Data.SqlTypes;
+using System.Globalization;
+using System.Linq;
 using System.Text;
+using System.Threading;
+using Microsoft.Crm.Sdk.Messages;
 
 namespace MarkMpn.Sql4Cds.Engine
 {
-    public struct SqlDate : INullable, IComparable
+    public struct SqlSmallDateTime : INullable, IComparable
     {
-        private SqlDateTime _dt;
+        private readonly DateTime? _dt;
 
-        public SqlDate(SqlDateTime dt)
+        public SqlSmallDateTime(DateTime? dt)
         {
-            _dt = dt.IsNull ? dt : dt.Value.Date;
+            if (dt == null)
+            {
+                _dt = dt;
+            }
+            else
+            {
+                // Value is rounded to the nearest minute
+                // https://learn.microsoft.com/en-us/sql/t-sql/functions/dateadd-transact-sql?view=sql-server-ver16#return-values-for-a-smalldatetime-date-and-a-second-or-fractional-seconds-datepart
+                _dt = new DateTime(dt.Value.Year, dt.Value.Month, dt.Value.Day, dt.Value.Hour, dt.Value.Minute, 0);
+
+                if (dt.Value.TimeOfDay.Seconds >= 30)
+                    _dt = _dt.Value.AddMinutes(1);
+            }
         }
 
-        public static readonly SqlDate Null = new SqlDate(SqlDateTime.Null);
+        public static readonly SqlSmallDateTime Null = new SqlSmallDateTime(null);
+
+        public static readonly SqlSmallDateTime MinValue = new SqlSmallDateTime(new DateTime(1900, 1, 1));
+
+        public static readonly SqlSmallDateTime MaxValue = new SqlSmallDateTime(new DateTime(2079, 6, 6, 23, 59, 0));
 
-        public bool IsNull => _dt.IsNull;
+        public bool IsNull => _dt == null;
 
         public int CompareTo(object obj)
         {
-            if (obj is SqlDate dt)
-                obj = dt._dt;
+            var value = (SqlSmallDateTime)obj;
+
+            if (IsNull)
+            {
+                if (!value.IsNull)
+                {
+                    return -1;
+                }
+                return 0;
+            }
+
+            if (value.IsNull)
+            {
+                return 1;
+            }
+
+            if (this < value)
+            {
+                return -1;
+            }
 
-            return _dt.CompareTo(obj);
+            if (this > value)
+            {
+                return 1;
+            }
+
+            return 0;
         }
 
         public override int GetHashCode()
         {
-            return _dt.GetHashCode();
+            return _dt?.GetHashCode() ?? 0;
         }
 
         public override bool Equals(object obj)
         {
-            if (obj is SqlDate dt)
-                obj = dt._dt;
+            if (!(obj is SqlSmallDateTime dt))
+                return false;
 
-            return _dt.Equals(obj);
+            return _dt == dt._dt;
         }
 
         public DateTime Value => _dt.Value;
 
-        public static SqlBoolean operator ==(SqlDate x, SqlDate y) => x._dt == y._dt;
+        public static SqlBoolean operator ==(SqlSmallDateTime x, SqlSmallDateTime y) => x.IsNull || y.IsNull ? SqlBoolean.Null : x._dt == y._dt;
 
-        public static SqlBoolean operator !=(SqlDate x, SqlDate y) => x._dt != y._dt;
+        public static SqlBoolean operator !=(SqlSmallDateTime x, SqlSmallDateTime y) => !(x == y);
 
-        public static SqlBoolean operator <(SqlDate x, SqlDate y) => x._dt < y._dt;
+        public static SqlBoolean operator <(SqlSmallDateTime x, SqlSmallDateTime y) => x.IsNull || y.IsNull ? SqlBoolean.Null : x._dt < y._dt;
 
-        public static SqlBoolean operator >(SqlDate x, SqlDate y) => x._dt > y._dt;
+        public static SqlBoolean operator >(SqlSmallDateTime x, SqlSmallDateTime y) => x.IsNull || y.IsNull ? SqlBoolean.Null : x._dt > y._dt;
 
-        public static SqlBoolean operator <=(SqlDate x, SqlDate y) => x._dt <= y._dt;
+        public static SqlBoolean operator <=(SqlSmallDateTime x, SqlSmallDateTime y) => x.IsNull || y.IsNull ? SqlBoolean.Null : x._dt <= y._dt;
 
-        public static SqlBoolean operator >=(SqlDate x, SqlDate y) => x._dt >= y._dt;
+        public static SqlBoolean operator >=(SqlSmallDateTime x, SqlSmallDateTime y) => x.IsNull || y.IsNull ? SqlBoolean.Null : x._dt >= y._dt;
 
-        public static implicit operator SqlDateTime(SqlDate dt)
+        public static implicit operator SqlDateTime(SqlSmallDateTime dt)
         {
-            return dt._dt;
+            if (dt.IsNull)
+                return SqlDateTime.Null;
+
+            return dt._dt.Value;
         }
 
-        public static implicit operator SqlDateTime2(SqlDate dt)
+        public static implicit operator SqlSmallDateTime(SqlDateTime dt)
         {
-            return dt._dt;
+            if (dt.IsNull)
+                return Null;
+
+            return new SqlSmallDateTime(dt.Value);
         }
 
-        public static implicit operator SqlDateTimeOffset(SqlDate dt)
+        public static implicit operator SqlDateTime2(SqlSmallDateTime dt)
         {
-            return dt._dt;
+            if (dt.IsNull)
+                return SqlDateTime2.Null;
+
+            return new SqlDateTime2(dt.Value);
         }
 
-        public static implicit operator SqlDate(SqlDateTime dt)
+        public static implicit operator SqlSmallDateTime(SqlDateTime2 dt)
         {
-            return new SqlDate(dt);
+            if (dt.IsNull)
+                return Null;
+
+            return new SqlSmallDateTime(dt.Value);
         }
 
-        public static implicit operator SqlDate(SqlDateTime2 dt)
+        public static implicit operator SqlDateTimeOffset(SqlSmallDateTime dt)
         {
-            return new SqlDate(dt);
+            if (dt.IsNull)
+                return SqlDateTimeOffset.Null;
+
+            return new SqlDateTimeOffset(dt.Value);
         }
 
-        public static implicit operator SqlDate(SqlDateTimeOffset dt)
+        public static implicit operator SqlSmallDateTime(SqlDateTimeOffset dt)
         {
-            return new SqlDate(dt);
+            if (dt.IsNull)
+                return Null;
+
+            return new SqlSmallDateTime(dt.Value.DateTime);
         }
 
-        public static implicit operator SqlDate(SqlString str)
+        public static implicit operator SqlDate(SqlSmallDateTime dt)
         {
-            return new SqlDate((SqlDateTime)str);
+            if (dt.IsNull)
+                return SqlDate.Null;
+
+            return new SqlDate(dt.Value);
         }
 
-        public override string ToString()
+        public static implicit operator SqlSmallDateTime(SqlDate dt)
+        {
+            if (dt.IsNull)
+                return Null;
+
+            return new SqlSmallDateTime(dt.Value);
+        }
+
+        public static implicit operator SqlTime(SqlSmallDateTime dt)
+        {
+            if (dt.IsNull)
+                return SqlTime.Null;
+
+            return new SqlTime(dt.Value.TimeOfDay);
+        }
+
+        public static implicit operator SqlSmallDateTime(SqlTime dt)
         {
-            return _dt.ToString();
+            if (dt.IsNull)
+                return Null;
+
+            return new SqlSmallDateTime(new DateTime(1900, 1, 1) + dt.Value);
         }
     }
 
-    public struct SqlTime : INullable, IComparable
+    public struct SqlDate : INullable, IComparable
     {
-        private SqlDateTime _dt;
+        private readonly DateTime? _dt;
+
+        public SqlDate(DateTime? dt)
+        {
+            _dt = dt;
+        }
+
+        public static readonly SqlDate Null = new SqlDate(null);
+
+        public bool IsNull => _dt == null;
 
-        public SqlTime(SqlDateTime dt)
+        public int CompareTo(object obj)
+        {
+            var value = (SqlDate)obj;
+
+            if (IsNull)
+            {
+                if (!value.IsNull)
+                {
+                    return -1;
+                }
+                return 0;
+            }
+
+            if (value.IsNull)
+            {
+                return 1;
+            }
+
+            if (this < value)
+            {
+                return -1;
+            }
+
+            if (this > value)
+            {
+                return 1;
+            }
+
+            return 0;
+        }
+
+        public override int GetHashCode()
+        {
+            return _dt?.GetHashCode() ?? 0;
+        }
+
+        public override bool Equals(object obj)
+        {
+            if (!(obj is SqlDate dt))
+                return false;
+
+            return _dt == dt._dt;
+        }
+
+        public DateTime Value => _dt.Value;
+
+        public static SqlBoolean operator ==(SqlDate x, SqlDate y) => x.IsNull || y.IsNull ? SqlBoolean.Null : x._dt == y._dt;
+
+        public static SqlBoolean operator !=(SqlDate x, SqlDate y) => !(x == y);
+
+        public static SqlBoolean operator <(SqlDate x, SqlDate y) => x.IsNull || y.IsNull ? SqlBoolean.Null : x._dt < y._dt;
+
+        public static SqlBoolean operator >(SqlDate x, SqlDate y) => x.IsNull || y.IsNull ? SqlBoolean.Null : x._dt > y._dt;
+
+        public static SqlBoolean operator <=(SqlDate x, SqlDate y) => x.IsNull || y.IsNull ? SqlBoolean.Null : x._dt <= y._dt;
+
+        public static SqlBoolean operator >=(SqlDate x, SqlDate y) => x.IsNull || y.IsNull ? SqlBoolean.Null : x._dt >= y._dt;
+
+        public static implicit operator SqlDateTime(SqlDate dt)
+        {
+            if (dt.IsNull)
+                return SqlDateTime.Null;
+
+            return dt._dt.Value;
+        }
+
+        public static implicit operator SqlDate(SqlDateTime dt)
+        {
+            if (dt.IsNull)
+                return Null;
+
+            return new SqlDate(dt.Value.Date);
+        }
+
+        public static implicit operator SqlDate(DateTime? dt)
         {
-            _dt = dt.IsNull ? dt : new DateTime(1900, 1, 1).AddTicks(dt.TimeTicks * TimeSpan.TicksPerSecond / SqlDateTime.SQLTicksPerSecond);
+            return new SqlDate(dt);
         }
 
+        public override string ToString()
+        {
+            return _dt?.ToString() ?? "Null";
+        }
+
+        /// <summary>
+        /// Converts a string literal to the equivalent <see cref="SqlDate"/> value
+        /// </summary>
+        /// <see href="https://learn.microsoft.com/en-us/sql/t-sql/data-types/date-transact-sql?view=sql-server-ver16#supported-string-literal-formats-for-date"/>
+        /// <param name="value">The string literal to parse</param>
+        /// <param name="dateFormat">The current DATEFORMAT setting to control the expected formats</param>
+        /// <param name="date">The parsed version of the date</param>
+        /// <returns><see langword="true"/> if the <paramref name="value"/> was parsed successfully, or <see langword="false"/> otherwise</returns>
+        internal static bool TryParse(SqlString value, DateFormat dateFormat, out SqlDate date)
+        {
+            return SqlDateParsing.TryParse(value, dateFormat, out date);
+        }
+    }
+
+    public struct SqlTime : INullable, IComparable
+    {
+        private readonly TimeSpan? _ts;
+        private static readonly DateTime _defaultDate = new DateTime(1900, 1, 1);
+
         public SqlTime(TimeSpan? ts)
         {
-            _dt = ts == null ? SqlDateTime.Null : new DateTime(1900, 1, 1).Add(ts.Value);
+            _ts = ts;
         }
 
-        public static readonly SqlTime Null = new SqlTime(SqlDateTime.Null);
+        public static readonly SqlTime Null = new SqlTime(null);
 
-        public bool IsNull => _dt.IsNull;
+        public bool IsNull => _ts == null;
 
         public int CompareTo(object obj)
         {
-            if (obj is SqlTime dt)
-                obj = dt._dt;
+            var value = (SqlTime)obj;
+
+            if (IsNull)
+            {
+                if (!value.IsNull)
+                {
+                    return -1;
+                }
+                return 0;
+            }
+
+            if (value.IsNull)
+            {
+                return 1;
+            }
+
+            if (this < value)
+            {
+                return -1;
+            }
 
-            return _dt.CompareTo(obj);
+            if (this > value)
+            {
+                return 1;
+            }
+
+            return 0;
         }
 
         public override int GetHashCode()
         {
-            return _dt.GetHashCode();
+            return _ts?.GetHashCode() ?? 0;
         }
 
         public override bool Equals(object obj)
         {
-            if (obj is SqlTime dt)
-                obj = dt._dt;
+            if (!(obj is SqlTime dt))
+                return false;
 
-            return _dt.Equals(obj);
+            return _ts == dt._ts;
         }
 
-        public TimeSpan Value => _dt.Value.TimeOfDay;
+        public TimeSpan Value => _ts.Value;
 
-        public static SqlBoolean operator ==(SqlTime x, SqlTime y) => x._dt == y._dt;
+        public static SqlBoolean operator ==(SqlTime x, SqlTime y) => x.IsNull || y.IsNull ? SqlBoolean.Null : x._ts == y._ts;
 
-        public static SqlBoolean operator !=(SqlTime x, SqlTime y) => x._dt != y._dt;
+        public static SqlBoolean operator !=(SqlTime x, SqlTime y) => !(x == y);
 
-        public static SqlBoolean operator <(SqlTime x, SqlTime y) => x._dt < y._dt;
+        public static SqlBoolean operator <(SqlTime x, SqlTime y) => x.IsNull || y.IsNull ? SqlBoolean.Null : x._ts < y._ts;
 
-        public static SqlBoolean operator >(SqlTime x, SqlTime y) => x._dt > y._dt;
+        public static SqlBoolean operator >(SqlTime x, SqlTime y) => x.IsNull || y.IsNull ? SqlBoolean.Null : x._ts > y._ts;
 
-        public static SqlBoolean operator <=(SqlTime x, SqlTime y) => x._dt <= y._dt;
+        public static SqlBoolean operator <=(SqlTime x, SqlTime y) => x.IsNull || y.IsNull ? SqlBoolean.Null : x._ts <= y._ts;
 
-        public static SqlBoolean operator >=(SqlTime x, SqlTime y) => x._dt >= y._dt;
+        public static SqlBoolean operator >=(SqlTime x, SqlTime y) => x.IsNull || y.IsNull ? SqlBoolean.Null : x._ts >= y._ts;
 
         public static implicit operator SqlDateTime(SqlTime dt)
         {
-            return dt._dt;
-        }
+            if (dt.IsNull)
+                return SqlDateTime.Null;
 
+            return _defaultDate + dt._ts.Value;
+        }
+        /*
         public static implicit operator SqlDateTime2(SqlTime dt)
         {
-            return dt._dt;
+            if (dt.IsNull)
+                return SqlDateTime2.Null;
+
+            return _defaultDate + dt._ts.Value;
         }
 
         public static implicit operator SqlDateTimeOffset(SqlTime dt)
         {
-            return dt._dt;
-        }
+            if (dt.IsNull)
+                return SqlDateTimeOffset.Null;
 
+            return (DateTimeOffset)(_defaultDate + dt._ts.Value);
+        }
+        */
         public static implicit operator SqlTime(SqlDateTime dt)
         {
-            return new SqlTime(dt);
-        }
+            if (dt.IsNull)
+                return Null;
 
+            return new SqlTime(dt.Value.TimeOfDay);
+        }
+        /*
         public static implicit operator SqlTime(SqlDateTime2 dt)
         {
-            return new SqlTime(dt);
+            if (dt.IsNull)
+                return Null;
+
+            return new SqlTime(dt.Value.TimeOfDay);
         }
 
         public static implicit operator SqlTime(SqlDateTimeOffset dt)
         {
-            return new SqlTime(dt);
-        }
+            if (dt.IsNull)
+                return Null;
 
+            return new SqlTime(dt.Value.TimeOfDay);
+        }
+        */
         public static implicit operator SqlTime(SqlString str)
         {
-            return new SqlTime((SqlDateTime)str);
+            return (SqlTime)(SqlDateTime)str;
+        }
+
+        public static implicit operator SqlTime(TimeSpan? ts)
+        {
+            return new SqlTime(ts);
         }
 
         public override string ToString()
         {
-            return _dt.ToString();
+            return _ts?.ToString() ?? "Null";
         }
     }
 
     public struct SqlDateTime2 : INullable, IComparable
     {
-        private SqlDateTime _dt;
+        private readonly DateTime? _dt;
+        private static readonly string[] x_DateTimeFormats = new string[8] { "MMM d yyyy hh:mm:ss:ffftt", "MMM d yyyy hh:mm:ss:fff", "d MMM yyyy hh:mm:ss:ffftt", "d MMM yyyy hh:mm:ss:fff", "hh:mm:ss:ffftt", "hh:mm:ss:fff", "yyMMdd", "yyyyMMdd" };
+        private static readonly DateTime _defaultDate = new DateTime(1900, 1, 1);
 
-        public SqlDateTime2(SqlDateTime dt)
+        public SqlDateTime2(DateTime? dt)
         {
             _dt = dt;
         }
 
-        public static readonly SqlDateTime2 Null = new SqlDateTime2(SqlDateTime.Null);
+        public static readonly SqlDateTime2 Null = new SqlDateTime2(null);
 
-        public bool IsNull => _dt.IsNull;
+        public bool IsNull => _dt == null;
 
         public int CompareTo(object obj)
         {
-            if (obj is SqlDateTime2 dt)
-                obj = dt._dt;
+            var value = (SqlDateTime2)obj;
+
+            if (IsNull)
+            {
+                if (!value.IsNull)
+                {
+                    return -1;
+                }
+                return 0;
+            }
+
+            if (value.IsNull)
+            {
+                return 1;
+            }
+
+            if (this < value)
+            {
+                return -1;
+            }
 
-            return _dt.CompareTo(obj);
+            if (this > value)
+            {
+                return 1;
+            }
+
+            return 0;
         }
 
         public override int GetHashCode()
         {
-            return _dt.GetHashCode();
+            return _dt?.GetHashCode() ?? 0;
         }
 
         public override bool Equals(object obj)
         {
-            if (obj is SqlDateTime2 dt)
-                obj = dt._dt;
+            if (!(obj is SqlDateTime2 value))
+                return false;
 
-            return _dt.Equals(obj);
+            return _dt == value._dt;
         }
 
         public DateTime Value => _dt.Value;
 
-        public static SqlBoolean operator ==(SqlDateTime2 x, SqlDateTime2 y) => x._dt == y._dt;
+        public static SqlBoolean operator ==(SqlDateTime2 x, SqlDateTime2 y) => x.IsNull || y.IsNull ? SqlBoolean.Null : x._dt == y._dt;
 
-        public static SqlBoolean operator !=(SqlDateTime2 x, SqlDateTime2 y) => x._dt != y._dt;
+        public static SqlBoolean operator !=(SqlDateTime2 x, SqlDateTime2 y) => !(x == y);
 
-        public static SqlBoolean operator <(SqlDateTime2 x, SqlDateTime2 y) => x._dt < y._dt;
+        public static SqlBoolean operator <(SqlDateTime2 x, SqlDateTime2 y) => x.IsNull || y.IsNull ? SqlBoolean.Null : x._dt < y._dt;
 
-        public static SqlBoolean operator >(SqlDateTime2 x, SqlDateTime2 y) => x._dt > y._dt;
+        public static SqlBoolean operator >(SqlDateTime2 x, SqlDateTime2 y) => x.IsNull || y.IsNull ? SqlBoolean.Null : x._dt > y._dt;
 
-        public static SqlBoolean operator <=(SqlDateTime2 x, SqlDateTime2 y) => x._dt <= y._dt;
+        public static SqlBoolean operator <=(SqlDateTime2 x, SqlDateTime2 y) => x.IsNull || y.IsNull ? SqlBoolean.Null : x._dt <= y._dt;
 
-        public static SqlBoolean operator >=(SqlDateTime2 x, SqlDateTime2 y) => x._dt >= y._dt;
+        public static SqlBoolean operator >=(SqlDateTime2 x, SqlDateTime2 y) => x.IsNull || y.IsNull ? SqlBoolean.Null : x._dt >= y._dt;
 
         public static implicit operator SqlDateTime(SqlDateTime2 dt)
         {
-            return dt._dt;
+            if (dt.IsNull)
+                return SqlDateTime.Null;
+
+            return (SqlDateTime)dt._dt.Value;
         }
 
         public static implicit operator SqlDate(SqlDateTime2 dt)
         {
-            return dt._dt;
+            if (dt.IsNull)
+                return SqlDate.Null;
+
+            return (SqlDate)dt._dt.Value.Date;
         }
 
         public static implicit operator SqlTime(SqlDateTime2 dt)
         {
-            return dt._dt;
-        }
+            if (dt.IsNull)
+                return SqlTime.Null;
 
+            return (SqlTime)dt._dt.Value.TimeOfDay;
+        }
+        /*
         public static implicit operator SqlDateTimeOffset(SqlDateTime2 dt)
         {
-            return dt._dt;
-        }
+            if (dt.IsNull)
+                return SqlDateTimeOffset.Null;
 
+            return (DateTimeOffset)dt._dt.Value;
+        }
+        */
         public static implicit operator SqlDateTime2(SqlDateTime dt)
         {
-            return new SqlDateTime2(dt);
+            if (dt.IsNull)
+                return Null;
+
+            return new SqlDateTime2(dt.Value);
         }
 
         public static implicit operator SqlDateTime2(SqlDate dt)
         {
-            return new SqlDateTime2(dt);
+            if (dt.IsNull)
+                return Null;
+
+            return new SqlDateTime2(dt.Value);
         }
 
         public static implicit operator SqlDateTime2(SqlTime dt)
         {
-            return new SqlDateTime2(dt);
-        }
+            if (dt.IsNull)
+                return Null;
 
+            return new SqlDateTime2(_defaultDate + dt.Value);
+        }
+        /*
         public static implicit operator SqlDateTime2(SqlDateTimeOffset dt)
+        {
+            if (dt.IsNull)
+                return Null;
+
+            return new SqlDateTime2(dt.Value.DateTime);
+        }
+        */
+        public static implicit operator SqlDateTime2(DateTime? dt)
         {
             return new SqlDateTime2(dt);
         }
 
         public static implicit operator SqlDateTime2(SqlString str)
         {
-            return new SqlDateTime2((SqlDateTime)str);
+            if (str.IsNull)
+                return Null;
+
+            DateTime value;
+            try
+            {
+                value = DateTime.Parse(str.Value, CultureInfo.InvariantCulture);
+            }
+            catch (FormatException)
+            {
+                DateTimeFormatInfo provider = (DateTimeFormatInfo)Thread.CurrentThread.CurrentCulture.GetFormat(typeof(DateTimeFormatInfo));
+                value = DateTime.ParseExact(str.Value, x_DateTimeFormats, provider, DateTimeStyles.AllowWhiteSpaces);
+            }
+
+            return new SqlDateTime2((DateTime?)value);
         }
 
         public override string ToString()
         {
-            return _dt.ToString();
+            return _dt?.ToString() ?? "Null";
         }
     }
 
     public struct SqlDateTimeOffset : INullable, IComparable
     {
-        private DateTimeOffset? _dt;
-
-        public SqlDateTimeOffset(SqlDateTime dt)
-        {
-            _dt = dt.IsNull ? (DateTimeOffset?)null : dt.Value;
-        }
+        private readonly DateTimeOffset? _dt;
+        private static readonly DateTime _defaultDate = new DateTime(1900, 1, 1, 0, 0, 0, DateTimeKind.Utc);
 
         public SqlDateTimeOffset(DateTimeOffset? dt)
         {
@@ -307,83 +607,124 @@ public SqlDateTimeOffset(DateTimeOffset? dt)
 
         public int CompareTo(object obj)
         {
-            if (obj is SqlDateTimeOffset dt)
-                obj = dt._dt;
+            var value = (SqlDateTimeOffset)obj;
+
+            if (IsNull)
+            {
+                if (!value.IsNull)
+                {
+                    return -1;
+                }
+                return 0;
+            }
+
+            if (value.IsNull)
+            {
+                return 1;
+            }
 
-            if (_dt == null)
-                return obj == null ? 0 : -1;
+            if (this < value)
+            {
+                return -1;
+            }
 
-            if (obj == null)
+            if (this > value)
+            {
                 return 1;
+            }
 
-            return _dt.Value.CompareTo((DateTimeOffset) obj);
+            return 0;
         }
 
         public override int GetHashCode()
         {
-            return _dt.GetHashCode();
+            return _dt?.GetHashCode() ?? 0;
         }
 
         public override bool Equals(object obj)
         {
-            if (obj is SqlDateTimeOffset dt)
-                obj = dt._dt;
+            if (!(obj is SqlDateTimeOffset dt))
+                return false;
 
-            return _dt.Equals(obj);
+            return _dt == dt._dt;
         }
 
         public DateTimeOffset Value => _dt.Value;
 
-        public static SqlBoolean operator ==(SqlDateTimeOffset x, SqlDateTimeOffset y) => x._dt == y._dt;
+        public static SqlBoolean operator ==(SqlDateTimeOffset x, SqlDateTimeOffset y) => x.IsNull || y.IsNull ? SqlBoolean.Null : x._dt == y._dt;
 
-        public static SqlBoolean operator !=(SqlDateTimeOffset x, SqlDateTimeOffset y) => x._dt != y._dt;
+        public static SqlBoolean operator !=(SqlDateTimeOffset x, SqlDateTimeOffset y) => !(x._dt != y._dt);
 
-        public static SqlBoolean operator <(SqlDateTimeOffset x, SqlDateTimeOffset y) => x._dt < y._dt;
+        public static SqlBoolean operator <(SqlDateTimeOffset x, SqlDateTimeOffset y) => x.IsNull || y.IsNull ? SqlBoolean.Null : x._dt < y._dt;
 
-        public static SqlBoolean operator >(SqlDateTimeOffset x, SqlDateTimeOffset y) => x._dt > y._dt;
+        public static SqlBoolean operator >(SqlDateTimeOffset x, SqlDateTimeOffset y) => x.IsNull || y.IsNull ? SqlBoolean.Null : x._dt > y._dt;
 
-        public static SqlBoolean operator <=(SqlDateTimeOffset x, SqlDateTimeOffset y) => x._dt <= y._dt;
+        public static SqlBoolean operator <=(SqlDateTimeOffset x, SqlDateTimeOffset y) => x.IsNull || y.IsNull ? SqlBoolean.Null : x._dt <= y._dt;
 
-        public static SqlBoolean operator >=(SqlDateTimeOffset x, SqlDateTimeOffset y) => x._dt >= y._dt;
+        public static SqlBoolean operator >=(SqlDateTimeOffset x, SqlDateTimeOffset y) => x.IsNull || y.IsNull ? SqlBoolean.Null : x._dt >= y._dt;
 
         public static implicit operator SqlDateTime(SqlDateTimeOffset dt)
         {
-            return dt._dt == null ? SqlDateTime.Null : (SqlDateTime)dt._dt.Value.DateTime;
+            if (dt.IsNull)
+                return SqlDateTime.Null;
+
+            return (SqlDateTime)dt._dt.Value.DateTime;
         }
 
         public static implicit operator SqlDate(SqlDateTimeOffset dt)
         {
-            return dt._dt == null ? SqlDate.Null : (SqlDate)(SqlDateTime)dt._dt.Value.DateTime;
+            if (dt.IsNull)
+                return SqlDateTime.Null;
+
+            return (SqlDate)dt._dt.Value.Date;
         }
 
         public static implicit operator SqlTime(SqlDateTimeOffset dt)
         {
-            return dt._dt == null ? SqlTime.Null : (SqlTime)(SqlDateTime)dt._dt.Value.DateTime;
+            if (dt.IsNull)
+                return SqlTime.Null;
+
+            return (SqlTime)dt._dt.Value.TimeOfDay;
         }
 
         public static implicit operator SqlDateTime2(SqlDateTimeOffset dt)
         {
-            return dt._dt == null ? SqlDateTime2.Null : (SqlDateTime2)(SqlDateTime)dt._dt.Value.DateTime;
+            if (dt.IsNull)
+                return SqlDateTime.Null;
+
+            return (SqlDateTime2)dt._dt.Value.DateTime;
         }
 
         public static implicit operator SqlDateTimeOffset(SqlDateTime dt)
         {
-            return new SqlDateTimeOffset(dt);
+            if (dt.IsNull)
+                return Null;
+
+            return new SqlDateTimeOffset(DateTime.SpecifyKind(dt.Value, DateTimeKind.Utc));
         }
 
         public static implicit operator SqlDateTimeOffset(SqlDate dt)
         {
-            return new SqlDateTimeOffset(dt);
+            if (dt.IsNull)
+                return Null;
+
+            return new SqlDateTimeOffset(DateTime.SpecifyKind(dt.Value, DateTimeKind.Utc));
         }
 
         public static implicit operator SqlDateTimeOffset(SqlTime dt)
         {
-            return new SqlDateTimeOffset(dt);
+            if (dt.IsNull)
+                return Null;
+
+            return new SqlDateTimeOffset(_defaultDate + dt.Value);
         }
 
         public static implicit operator SqlDateTimeOffset(SqlDateTime2 dt)
         {
-            return new SqlDateTimeOffset(dt);
+            if (dt.IsNull)
+                return Null;
+
+            return new SqlDateTimeOffset(DateTime.SpecifyKind(dt.Value, DateTimeKind.Utc));
         }
 
         public static implicit operator SqlDateTimeOffset(SqlString str)
@@ -395,9 +736,517 @@ public static implicit operator SqlDateTimeOffset(SqlString str)
             return new SqlDateTimeOffset(dto);
         }
 
+        public static implicit operator SqlDateTimeOffset(DateTimeOffset? dt)
+        {
+            return new SqlDateTimeOffset(dt);
+        }
+
         public override string ToString()
         {
-            return _dt.ToString();
+            return _dt?.ToString() ?? "Null";
+        }
+    }
+
+    /// <summary>
+    /// Sets the DATEFORMAT that is used to parse string literals into dates
+    /// </summary>
+    /// <see href="https://learn.microsoft.com/en-us/sql/t-sql/statements/set-dateformat-transact-sql?view=sql-server-ver16"/>
+    enum DateFormat
+    {
+        mdy,
+        dmy,
+        ymd,
+        ydm,
+        myd,
+        dym
+    }
+
+    /// <summary>
+    /// Provides methods to parse string literals into various date/time types
+    /// </summary>
+    /// <remarks>
+    /// The built-in conversion for strings to SqlDateTime does not respect the DATEFORMAT setting. The
+    /// conversion from strings to the other date/time/datetime2/datetimeoffset types also support a different
+    /// set of formats, so we need to implement them here. Those types use a consistent set of formats between
+    /// them, so we implement them here in the most precise format (datetimeoffset) and then down-cast the result
+    /// to the other types as necessary.
+    /// </remarks>
+    static class SqlDateParsing
+    {
+        /// <summary>
+        /// Converts a string literal to the equivalent <see cref="SqlDate"/> value
+        /// </summary>
+        /// <see href="https://learn.microsoft.com/en-us/sql/t-sql/data-types/date-transact-sql?view=sql-server-ver16#supported-string-literal-formats-for-date"/>
+        /// <param name="value">The string literal to parse</param>
+        /// <param name="dateFormat">The current DATEFORMAT setting to control the expected formats</param>
+        /// <param name="date">The parsed version of the date</param>
+        /// <returns><see langword="true"/> if the <paramref name="value"/> was parsed successfully, or <see langword="false"/> otherwise</returns>
+        public static bool TryParse(SqlString value, DateFormat dateFormat, out SqlDate date)
+        {
+            var ret = TryParse(value, dateFormat, out SqlDateTimeOffset dto);
+            date = dto;
+            return ret;
+        }
+
+        /// <summary>
+        /// Converts a string literal to the equivalent <see cref="SqlDateTime2"/> value
+        /// </summary>
+        /// <see href="https://learn.microsoft.com/en-us/sql/t-sql/data-types/datetime2-transact-sql?view=sql-server-ver16#supported-string-literal-formats-for-datetime2"/>
+        /// <param name="value">The string literal to parse</param>
+        /// <param name="dateFormat">The current DATEFORMAT setting to control the expected formats</param>
+        /// <param name="dateTime2">The parsed version of the datetime</param>
+        /// <returns><see langword="true"/> if the <paramref name="value"/> was parsed successfully, or <see langword="false"/> otherwise</returns>
+        public static bool TryParse(SqlString value, DateFormat dateFormat, out SqlDateTime2 dateTime2)
+        {
+            var ret = TryParse(value, dateFormat, out SqlDateTimeOffset dto);
+            dateTime2 = dto;
+            return ret;
+        }
+
+        /// <summary>
+        /// Converts a string literal to the equivalent <see cref="SqlTime"/> value
+        /// </summary>
+        /// <see href="https://learn.microsoft.com/en-us/sql/t-sql/data-types/time-transact-sql?view=sql-server-ver16#supported-string-literal-formats-for-time"/>
+        /// <param name="value">The string literal to parse</param>
+        /// <param name="dateFormat">The current DATEFORMAT setting to control the expected formats</param>
+        /// <param name="time">The parsed version of the time</param>
+        /// <returns><see langword="true"/> if the <paramref name="value"/> was parsed successfully, or <see langword="false"/> otherwise</returns>
+        public static bool TryParse(SqlString value, DateFormat dateFormat, out SqlTime time)
+        {
+            var ret = TryParse(value, dateFormat, out SqlDateTimeOffset dto);
+            time = dto;
+            return ret;
+        }
+
+        /// <summary>
+        /// Converts a string literal to the equivalent <see cref="SqlDateTime2"/> value
+        /// </summary>
+        /// <see href="https://learn.microsoft.com/en-us/sql/t-sql/data-types/datetimeoffset-transact-sql?view=sql-server-ver16#supported-string-literal-formats-for-datetimeoffset"/>
+        /// <param name="value">The string literal to parse</param>
+        /// <param name="dateFormat">The current DATEFORMAT setting to control the expected formats</param>
+        /// <param name="dateTimeOffset">The parsed version of the datetimeoffset</param>
+        /// <returns><see langword="true"/> if the <paramref name="value"/> was parsed successfully, or <see langword="false"/> otherwise</returns>
+        public static bool TryParse(SqlString value, DateFormat dateFormat, out SqlDateTimeOffset dateTimeOffset)
+        {
+            if (value.IsNull)
+            {
+                dateTimeOffset = SqlDateTimeOffset.Null;
+                return true;
+            }
+
+            // Allowed formats vary depending on format, but all formats are consistent combinations of
+            // year, month and day with different separators
+            string formatStringPart1;
+            string formatStringPart2;
+            string formatStringPart3;
+            string[] separators = new[] { "/", "-", "." };
+
+            switch (dateFormat)
+            {
+                case DateFormat.mdy:
+                    formatStringPart1 = "[M]M";
+                    formatStringPart2 = "[d]d";
+                    formatStringPart3 = "[yy]yy";
+                    break;
+
+                case DateFormat.myd:
+                    formatStringPart1 = "[M]M";
+                    formatStringPart2 = "[yy]yy";
+                    formatStringPart3 = "[d]d";
+                    break;
+
+                case DateFormat.dmy:
+                    formatStringPart1 = "[d]d";
+                    formatStringPart2 = "[M]M";
+                    formatStringPart3 = "[yy]yy";
+                    break;
+
+                case DateFormat.dym:
+                    formatStringPart1 = "[d]d";
+                    formatStringPart2 = "[yy]yy";
+                    formatStringPart3 = "[M]M";
+                    break;
+
+                case DateFormat.ymd:
+                    formatStringPart1 = "[yy]yy";
+                    formatStringPart2 = "[M]M";
+                    formatStringPart3 = "[d]d";
+                    break;
+
+                default:
+                    // ydm format is not supported for datetimeoffset/datetime2/date/time
+                    dateTimeOffset = SqlDateTimeOffset.Null;
+                    return false;
+            }
+
+            var numericFormatStrings = separators
+                .Select(s => $"{formatStringPart1}{s}{formatStringPart2}{s}{formatStringPart3}");
+
+            var alphaFormatStrings = new[]
+            {
+                "mon [dd][,] yyyy",
+                "mon dd[,] [yy]",
+                "mon yyyy [dd]",
+                "[dd] mon[,] yyyy",
+                "dd mon[,][yy]yy",
+                "dd [yy]yy mon",
+                "[dd] yyyy mon",
+                "yyyy mon [dd]",
+                "yyyy [dd] mon"
+            };
+
+            var isoFormatStrings = new[]
+            {
+                "yyyy-MM-dd",
+                "yyyyMMdd"
+            };
+
+            var unseparatedFormatStrings = new[]
+            {
+                "yyMMdd",
+                "yyyy"
+            };
+
+            var w3cFormatString = new[]
+            {
+                "yyyy-MM-ddK"
+            };
+
+            var timeFormatStrings = new[]
+            {
+                "HH:mm",
+                "HH:mm:ss",
+                "HH:mm:ss:fffffff",
+                "HH:mm:ss.fffffff",
+                "hh:mmtt",
+                "hh:mm:sstt",
+                "hh:mm:ss:ffffffftt",
+                "hh:mm:ss.ffffffftt",
+                "hhtt",
+                "hh tt"
+            };
+
+            var allDateFormats = numericFormatStrings
+                .Concat(alphaFormatStrings)
+                .Concat(isoFormatStrings)
+                .Concat(unseparatedFormatStrings)
+                .Concat(w3cFormatString)
+                .SelectMany(f => SqlToNetFormatString(f))
+                .ToArray();
+
+            var allTimeFormats = timeFormatStrings
+                .SelectMany(f => new[] { f, f + "K", f + " K" }) // Allow optional timezone with all time formats, with optional space
+                .SelectMany(f => SqlToNetFormatString(f))
+                .ToArray();
+
+            var allDateTimeFormats = allDateFormats
+                .Concat(allDateFormats.SelectMany(d => allTimeFormats.Select(t => d + " " + t)))
+                .ToArray();
+
+            if (!DateTimeOffset.TryParseExact(value.Value.Trim(), allDateTimeFormats, CultureInfo.InvariantCulture, DateTimeStyles.AssumeUniversal, out var parsed))
+            {
+                if (DateTimeOffset.TryParseExact(value.Value, allTimeFormats, CultureInfo.InvariantCulture, DateTimeStyles.AssumeUniversal, out parsed))
+                {
+                    dateTimeOffset = new DateTimeOffset(new DateTime(1900, 1, 1), parsed.Offset) + parsed.TimeOfDay;
+                    return true;
+                }
+
+                dateTimeOffset = SqlDateTimeOffset.Null;
+                return false;
+            }
+
+            dateTimeOffset = parsed;
+            return true;
+        }
+        /// <summary>
+        /// Converts a string literal to the equivalent <see cref="SqlDateTime"/> value
+        /// </summary>
+        /// <see href="https://learn.microsoft.com/en-us/sql/t-sql/data-types/datetime-transact-sql?view=sql-server-ver16#supported-string-literal-formats-for-datetime"/>
+        /// <param name="value">The string literal to parse</param>
+        /// <param name="dateFormat">The current DATEFORMAT setting to control the expected formats</param>
+        /// <param name="date">The parsed version of the date</param>
+        /// <returns><see langword="true"/> if the <paramref name="value"/> was parsed successfully, or <see langword="false"/> otherwise</returns>
+        public static bool TryParse(SqlString value, DateFormat dateFormat, out SqlDateTime date)
+        {
+            if (value.IsNull)
+            {
+                date = SqlDateTime.Null;
+                return true;
+            }
+
+            // Allowed formats vary depending on format, but all formats are consistent combinations of
+            // year, month and day with different separators
+            string formatStringPart1;
+            string formatStringPart2;
+            string formatStringPart3;
+            string formatString4DigitYearPart1;
+            string formatString4DigitYearPart2;
+            string[] separators = new[] { "/", "-", "." };
+
+            switch (dateFormat)
+            {
+                case DateFormat.mdy:
+                    formatStringPart1 = "[M]M";
+                    formatStringPart2 = "[d]d";
+                    formatStringPart3 = "[yy]yy";
+
+                    formatString4DigitYearPart1 = "[M]M";
+                    formatString4DigitYearPart2 = "[d]d";
+                    break;
+
+                case DateFormat.myd:
+                    formatStringPart1 = "[M]M";
+                    formatStringPart2 = "[yy]yy";
+                    formatStringPart3 = "[d]d";
+
+                    formatString4DigitYearPart1 = "[M]M";
+                    formatString4DigitYearPart2 = "[d]d";
+                    break;
+
+                case DateFormat.dmy:
+                    formatStringPart1 = "[d]d";
+                    formatStringPart2 = "[M]M";
+                    formatStringPart3 = "[yy]yy";
+
+                    formatString4DigitYearPart1 = "[d]d";
+                    formatString4DigitYearPart2 = "[M]M";
+                    break;
+
+                case DateFormat.dym:
+                    formatStringPart1 = "[d]d";
+                    formatStringPart2 = "[yy]yy";
+                    formatStringPart3 = "[M]M";
+
+                    formatString4DigitYearPart1 = "[d]d";
+                    formatString4DigitYearPart2 = "[M]M";
+                    break;
+
+                case DateFormat.ymd:
+                    formatStringPart1 = "[yy]yy";
+                    formatStringPart2 = "[M]M";
+                    formatStringPart3 = "[d]d";
+
+                    formatString4DigitYearPart1 = "[M]M";
+                    formatString4DigitYearPart2 = "[d]d";
+                    break;
+
+                case DateFormat.ydm:
+                    formatStringPart1 = "[yy]yy";
+                    formatStringPart2 = "[d]d";
+                    formatStringPart3 = "[M]M";
+
+                    formatString4DigitYearPart1 = "[d]d";
+                    formatString4DigitYearPart2 = "[M]M";
+                    break;
+
+                default:
+                    date = SqlDateTime.Null;
+                    return false;
+            }
+
+            var numericTimeFormatStrings = new[]
+            {
+                "",
+                "HH:mm",
+                "HH:mm:ss",
+                "HH:mm:ss:fff",
+                "HH:mm:ss.fff",
+                "hhtt",
+                "hh tt"
+            };
+
+            var numericFormatStrings = separators
+                .SelectMany(s => new[] {
+                    // Parts in the expected order
+                    $"{formatStringPart1}{s}{formatStringPart2}{s}{formatStringPart3}",
+
+                    // 4-digit year can come in any position and the other parts remain
+                    // in their original relative order
+                    $"yyyy{s}{formatString4DigitYearPart1}{s}{formatString4DigitYearPart2}",
+                    $"{formatString4DigitYearPart1}{s}yyyy{s}{formatString4DigitYearPart2}",
+                    $"{formatString4DigitYearPart1}{s}{formatString4DigitYearPart2}{s}yyyy",
+                })
+                .SelectMany(s => numericTimeFormatStrings.Select(t => s + " " + t));
+
+            var alphaFormatStrings = new[]
+            {
+                "mon [dd][,] yyyy",
+                "mon dd[,] [yy]",
+                "mon yyyy [dd]",
+                "[dd] mon[,] yyyy",
+                "dd mon[,][yy]yy",
+                "dd [yy]yy mon",
+                "[dd] yyyy mon",
+                "yyyy mon [dd]",
+                "yyyy [dd] mon"
+            };
+
+            var isoFormatStrings = new[]
+            {
+                "yyyy-MM-ddTHH:mm:ss",
+                "yyyy-MM-ddTHH:mm:ss.fff",
+                "yyyyMMdd",
+                "yyyyMMdd HH:mm:ss",
+                "yyyyMMdd HH:mm:ss.fff"
+            };
+
+            var allFormats = numericFormatStrings
+                .Concat(alphaFormatStrings)
+                .Concat(isoFormatStrings)
+                .SelectMany(f => SqlToNetFormatString(f))
+                .ToArray();
+
+            if (!DateTime.TryParseExact(value.Value.Trim(), allFormats, CultureInfo.InvariantCulture, DateTimeStyles.None, out var parsed))
+            {
+                date = SqlDateTime.Null;
+                return false;
+            }
+
+            date = parsed;
+            return true;
+        }
+
+        /// <summary>
+        /// Converts a SQL format string from the SQL Server documentation to the corresponding .NET format strings
+        /// </summary>
+        /// <param name="formatString"></param>
+        /// <returns></returns>
+        public static string[] SqlToNetFormatString(string formatString)
+        {
+            var parts = new List<string[]>();
+
+            // Parse the SQL format string into parts
+            // dd and [d]d both indicate a 1- or 2-digit day
+            // M and [M]M is a 1- or 2-digit month
+            // MM is a 2-digit month
+            // mon is an abbreviated or full month name
+            // yy is a 2-digit year
+            // yyyy is a 4-digit year
+            // [yy]yy is a 2- or 4-digit year
+            // HH is a 1- or 2-digit hour (24 hour clock)
+            // hh is a 1- or 2-digit hour (12 hour clock)
+            // mm is a 1- or 2-digit minute
+            // ss is a 1- or 2-digit second
+            // fff is a 1- to 3-digit fraction of a second
+            // fffffff is a 1- to 7-digit fraction of a second
+            // Anything else in [] is optional
+            // Anything else is a literal
+            //
+            // Note docs sometimes use m or mm for month - we need to change this to M or MM to consistently
+            // interpret it as a month instead of minutes
+            var optional = false;
+
+            for (var i = 0; i < formatString.Length; i++)
+            {
+                var length = formatString.Length - i;
+                var setOptional = false;
+
+                while (length >= 1)
+                {
+                    var part = formatString.Substring(i, length);
+
+                    if (part == "d" || part == "dd" || part == "[d]d")
+                    {
+                        parts.Add(new[] { "d", "dd" });
+                        break;
+                    }
+                    else if (part == "M" || part == "MM" || part == "[M]M")
+                    {
+                        parts.Add(new[] { "M", "MM" });
+                        break;
+                    }
+                    else if (part == "mon")
+                    {
+                        parts.Add(new[] { "MMM", "MMMM" });
+                        break;
+                    }
+                    else if (part == "yy")
+                    {
+                        parts.Add(new[] { "yy" });
+                        break;
+                    }
+                    else if (part == "yyyy")
+                    {
+                        parts.Add(new[] { "yyyy" });
+                        break;
+                    }
+                    else if (part == "[yy]yy")
+                    {
+                        parts.Add(new[] { "yy", "yyyy" });
+                        break;
+                    }
+                    else if (part == "HH")
+                    {
+                        parts.Add(new[] { "H", "HH" });
+                        break;
+                    }
+                    else if (part == "hh")
+                    {
+                        parts.Add(new[] { "h", "hh" });
+                        break;
+                    }
+                    else if (part == "mm")
+                    {
+                        parts.Add(new[] { "m", "mm" });
+                        break;
+                    }
+                    else if (part == "ss")
+                    {
+                        parts.Add(new[] { "s", "ss" });
+                        break;
+                    }
+                    else if (part == "fff")
+                    {
+                        parts.Add(new[] { "FFF" });
+                        break;
+                    }
+                    else if (part == "fffffff")
+                    {
+                        parts.Add(new[] { "FFFFFFF" });
+                        break;
+                    }
+                    else if (part == "[")
+                    {
+                        optional = true;
+                        setOptional = true;
+                        break;
+                    }
+                    else if (length == 1)
+                    {
+                        // Literal
+                        parts.Add(new[] { part });
+                        break;
+                    }
+                    else
+                    {
+                        // Try a shorter part
+                        length--;
+                    }
+                }
+
+                if (length == 0)
+                    throw new FormatException();
+
+                i += length - 1;
+
+                if (optional && !setOptional)
+                {
+                    parts[parts.Count - 1] = parts[parts.Count - 1].Concat(new[] { "" }).ToArray();
+                    optional = false;
+
+                    if (formatString[i + 1] == ']')
+                        i++;
+                    else
+                        throw new FormatException();
+                }
+            }
+
+            var formatStrings = parts[0];
+
+            for (var i = 1; i < parts.Count; i++)
+                formatStrings = formatStrings.SelectMany(s => parts[i].Select(p => s + p)).ToArray();
+
+            return formatStrings.Select(s => s.Trim().Replace("  ", " ")).ToArray();
         }
     }
 }
diff --git a/MarkMpn.Sql4Cds.Engine/SqlVariant.cs b/MarkMpn.Sql4Cds.Engine/SqlVariant.cs
index 803d9687..6606e386 100644
--- a/MarkMpn.Sql4Cds.Engine/SqlVariant.cs
+++ b/MarkMpn.Sql4Cds.Engine/SqlVariant.cs
@@ -11,16 +11,20 @@ namespace MarkMpn.Sql4Cds.Engine
 {
     struct SqlVariant : INullable, IComparable
     {
+        private readonly ExpressionExecutionContext _context;
+
         private SqlVariant(bool @null)
         {
             BaseType = DataTypeHelpers.Variant;
             Value = null;
+            _context = null;
         }
 
-        public SqlVariant(DataTypeReference baseType, INullable value)
+        public SqlVariant(DataTypeReference baseType, INullable value, ExpressionExecutionContext context)
         {
             BaseType = baseType ?? throw new ArgumentNullException(nameof(baseType));
             Value = value ?? throw new ArgumentNullException(nameof(value));
+            _context = context ?? throw new ArgumentNullException(nameof(context));
         }
 
         public static readonly SqlVariant Null = new SqlVariant(true);
@@ -77,8 +81,8 @@ sqlVariant.BaseType is SqlDataTypeReferenceWithCollation coll2 &&
             if (!SqlTypeConverter.CanMakeConsistentTypes(BaseType, sqlVariant.BaseType, null, null, null, out var consistentType))
                 throw new ArgumentException();
 
-            var value1 = SqlTypeConverter.GetConversion(BaseType, consistentType)(Value);
-            var value2 = SqlTypeConverter.GetConversion(sqlVariant.BaseType, consistentType)(sqlVariant.Value);
+            var value1 = SqlTypeConverter.GetConversion(BaseType, consistentType)(Value, _context);
+            var value2 = SqlTypeConverter.GetConversion(sqlVariant.BaseType, consistentType)(sqlVariant.Value, sqlVariant._context);
 
             if (!(value1 is IComparable comparable1))
                 throw new ArgumentException();
diff --git a/MarkMpn.Sql4Cds.Engine/Visitors/OptimizerHintValidatingVisitor.cs b/MarkMpn.Sql4Cds.Engine/Visitors/OptimizerHintValidatingVisitor.cs
index 99e622ec..f3f374b7 100644
--- a/MarkMpn.Sql4Cds.Engine/Visitors/OptimizerHintValidatingVisitor.cs
+++ b/MarkMpn.Sql4Cds.Engine/Visitors/OptimizerHintValidatingVisitor.cs
@@ -60,12 +60,18 @@ class OptimizerHintValidatingVisitor : TSqlFragmentVisitor
 
             // Ignore duplicate keys on insert, equivalent to IGNORE_DUP_KEY option on creation of index
             "IGNORE_DUP_KEY",
+
+            // Custom hint to disable converting DML source queries to constant scans
+            "NO_DIRECT_DML",
         };
 
         private static readonly HashSet<string> _removableSql4CdsQueryHints = new HashSet<string>(StringComparer.OrdinalIgnoreCase)
         {
             // DML-related hint can be removed from the SELECT statement sent to the TDS Endpoint
             "BYPASS_CUSTOM_PLUGIN_EXECUTION",
+            
+            // Custom hint to disable converting DML source queries to constant scans
+            "NO_DIRECT_DML",
         };
 
         private static readonly string[] _tsqlQueryHintPrefixes = new[]
diff --git a/MarkMpn.Sql4Cds.Engine/Visitors/SimpleFilterVisitor.cs b/MarkMpn.Sql4Cds.Engine/Visitors/SimpleFilterVisitor.cs
new file mode 100644
index 00000000..d11e0f8e
--- /dev/null
+++ b/MarkMpn.Sql4Cds.Engine/Visitors/SimpleFilterVisitor.cs
@@ -0,0 +1,118 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using MarkMpn.Sql4Cds.Engine.ExecutionPlan;
+using MarkMpn.Sql4Cds.Engine.FetchXml;
+using Microsoft.SqlServer.TransactSql.ScriptDom;
+
+namespace MarkMpn.Sql4Cds.Engine.Visitors
+{
+    /// <summary>
+    /// Flattens a nested AND/OR filter into a simple list of conditions
+    /// </summary>
+    class SimpleFilterVisitor : TSqlFragmentVisitor
+    {
+        private List<condition> _conditions;
+        private BooleanBinaryExpressionType _binaryType;
+        private bool _invalid;
+        private bool _setType;
+
+        public SimpleFilterVisitor()
+        {
+            _conditions = new List<condition>();
+            _binaryType = BooleanBinaryExpressionType.And;
+        }
+
+        public override void Visit(BooleanBinaryExpression node)
+        {
+            base.Visit(node);
+
+            if (_setType && _binaryType != node.BinaryExpressionType)
+                _invalid = true;
+
+            _binaryType = node.BinaryExpressionType;
+            _setType = true;
+        }
+
+        public override void Visit(BooleanExpression node)
+        {
+            base.Visit(node);
+
+            if (node is BooleanBinaryExpression)
+            {
+                // NOOP
+            }
+            else if (node is BooleanComparisonExpression cmp)
+            {
+                if (cmp.FirstExpression is ColumnReferenceExpression col1 && cmp.SecondExpression is ValueExpression lit2)
+                {
+                    if (!cmp.ComparisonType.TryConvertToFetchXml(out var op))
+                        _invalid = true;
+
+                    _conditions.Add(new condition
+                    {
+                        attribute = col1.MultiPartIdentifier.Identifiers.Last().Value,
+                        @operator = op,
+                        value = GetValue(lit2),
+                        IsVariable = !(lit2 is Literal)
+                    });
+                }
+                else if (cmp.FirstExpression is ValueExpression lit1 && cmp.SecondExpression is ColumnReferenceExpression col2)
+                {
+                    if (!cmp.ComparisonType.TransitiveComparison().TryConvertToFetchXml(out var op))
+                        _invalid = true;
+
+                    _conditions.Add(new condition
+                    {
+                        attribute = col2.MultiPartIdentifier.Identifiers.Last().Value,
+                        @operator = op,
+                        value = GetValue(lit1),
+                        IsVariable = !(lit1 is Literal)
+                    });
+                }
+                else
+                {
+                    // Unsupported
+                    _invalid = true;
+                }
+            }
+            else if (node is InPredicate @in && @in.Expression is ColumnReferenceExpression inCol && @in.Subquery == null && @in.Values.All(v => v is ValueExpression))
+            {
+                _conditions.Add(new condition
+                {
+                    attribute = inCol.MultiPartIdentifier.Identifiers.Last().Value,
+                    @operator = @operator.@in,
+                    Items = @in.Values.Cast<ValueExpression>().Select(l => new conditionValue { Value = GetValue(l), IsVariable = !(l is Literal) }).ToArray()
+                });
+            }
+            else
+            {
+                // Unsupported
+                _invalid = true;
+            }
+        }
+
+        private string GetValue(ValueExpression expr)
+        {
+            if (expr is Literal lit)
+                return lit.Value;
+
+            if (expr is GlobalVariableExpression g)
+                return g.Name;
+
+            if (expr is VariableReference v)
+                return v.Name;
+
+            throw new NotSupportedException("Unknown value type");
+        }
+
+        /// <summary>
+        /// The type of comparison used to combine the conditions. <see langword="null"/> if the filter is not .
+        /// </summary>
+        public BooleanBinaryExpressionType? BinaryType => _invalid ? null : (BooleanBinaryExpressionType?)_binaryType;
+
+        public IEnumerable<condition> Conditions => _conditions;
+    }
+}
diff --git a/MarkMpn.Sql4Cds.Engine/Visitors/TDSEndpointCompatibilityVisitor.cs b/MarkMpn.Sql4Cds.Engine/Visitors/TDSEndpointCompatibilityVisitor.cs
index 36cb1110..656421bf 100644
--- a/MarkMpn.Sql4Cds.Engine/Visitors/TDSEndpointCompatibilityVisitor.cs
+++ b/MarkMpn.Sql4Cds.Engine/Visitors/TDSEndpointCompatibilityVisitor.cs
@@ -458,5 +458,18 @@ public override void Visit(CommonTableExpression node)
 
             _ctes[node.ExpressionName.Value] = node;
         }
+
+        public override void Visit(GeneralSetCommand node)
+        {
+            if (node.CommandType == GeneralSetCommandType.DateFormat)
+            {
+                // SET DATEFORMAT does work, but isn't persisted correctly across the session
+                // Mark it as not compatible so we can track the selected format internally
+                // and pass it to the TDS Endpoint on each call as required.
+                IsCompatible = false;
+            }
+            
+            base.Visit(node);
+        }
     }
 }
diff --git a/MarkMpn.Sql4Cds.Export/ValueFormatter.cs b/MarkMpn.Sql4Cds.Export/ValueFormatter.cs
index 7bc6603a..9fb4911f 100644
--- a/MarkMpn.Sql4Cds.Export/ValueFormatter.cs
+++ b/MarkMpn.Sql4Cds.Export/ValueFormatter.cs
@@ -48,6 +48,10 @@ public static DbCellValue Format(object value, string dataTypeName, int? numeric
                     text = dt.ToString("yyyy-MM-dd HH:mm:ss" + (numericScale == 0 ? "" : ("." + new string('f', numericScale.Value))));
                 }
             }
+            else if (value is DateTimeOffset dto && !localFormatDates)
+            {
+                text = dto.ToString("yyyy-MM-dd HH:mm:ss" + (numericScale == 0 ? "" : ("." + new string('f', numericScale.Value))) + " zzz");
+            }
             else if (value is TimeSpan ts && !localFormatDates)
             {
                 text = ts.ToString("hh\\:mm\\:ss" + (numericScale == 0 ? "" : ("\\." + new string('f', numericScale.Value))));
diff --git a/MarkMpn.Sql4Cds.XTB/Images/LargeIcon_Smooth.png b/MarkMpn.Sql4Cds.XTB/Images/LargeIcon_Smooth.png
new file mode 100644
index 00000000..2bb8b0ad
Binary files /dev/null and b/MarkMpn.Sql4Cds.XTB/Images/LargeIcon_Smooth.png differ