Support for rust_decimal::Decimal

Cargo.toml

@@ -49,7 +49,7 @@ offline = [ "sqlx-macros/offline", "sqlx-core/offline" ]
 # intended mainly for CI and docs
 all = [ "tls", "all-databases", "all-types" ]
 all-databases = [ "mysql", "sqlite", "postgres", "mssql", "any" ]
-all-types = [ "bigdecimal", "json", "time", "chrono", "ipnetwork", "uuid" ]
+all-types = [ "bigdecimal", "decimal", "json", "time", "chrono", "ipnetwork", "uuid" ]
 
 # runtime
 runtime-async-std = [ "sqlx-core/runtime-async-std", "sqlx-macros/runtime-async-std" ]
@@ -65,6 +65,7 @@ mssql = [ "sqlx-core/mssql", "sqlx-macros/mssql" ]
 
 # types
 bigdecimal = ["sqlx-core/bigdecimal", "sqlx-macros/bigdecimal"]
+decimal = ["sqlx-core/decimal"]
 chrono = [ "sqlx-core/chrono", "sqlx-macros/chrono" ]
 ipnetwork = [ "sqlx-core/ipnetwork", "sqlx-macros/ipnetwork" ]
 uuid = [ "sqlx-core/uuid", "sqlx-macros/uuid" ]

sqlx-core/Cargo.toml

@@ -24,8 +24,9 @@ mssql = [ "uuid", "encoding_rs", "regex" ]
 any = []
 
 # types
-all-types = [ "chrono", "time", "bigdecimal", "ipnetwork", "json", "uuid" ]
+all-types = [ "chrono", "time", "bigdecimal", "decimal", "ipnetwork", "json", "uuid" ]
 bigdecimal = [ "bigdecimal_", "num-bigint" ]
+decimal = [ "rust_decimal", "num-bigint", "num-traits" ]
 json = [ "serde", "serde_json" ]
 
 # runtimes
@@ -41,6 +42,8 @@ atoi = "0.3.2"
 sqlx-rt = { path = "../sqlx-rt", version = "0.1.0-pre" }
 base64 = { version = "0.12.1", default-features = false, optional = true, features = [ "std" ] }
 bigdecimal_ = { version = "0.1.0", optional = true, package = "bigdecimal" }
+rust_decimal = { version = "1.6.0", optional = true }
+num-traits = { version = "0.2.12", optional = true }
 bitflags = { version = "1.2.1", default-features = false }
 bytes = "0.5.4"
 byteorder = { version = "1.3.4", default-features = false, features = [ "std" ] }

sqlx-core/src/mysql/types/decimal.rs

@@ -0,0 +1,29 @@
+use rust_decimal::Decimal;
+
+use crate::decode::Decode;
+use crate::encode::{Encode, IsNull};
+use crate::error::BoxDynError;
+use crate::mysql::io::MySqlBufMutExt;
+use crate::mysql::protocol::text::ColumnType;
+use crate::mysql::{MySql, MySqlTypeInfo, MySqlValueRef};
+use crate::types::Type;
+
+impl Type<MySql> for Decimal {
+    fn type_info() -> MySqlTypeInfo {
+        MySqlTypeInfo::binary(ColumnType::NewDecimal)
+    }
+}
+
+impl Encode<'_, MySql> for Decimal {
+    fn encode_by_ref(&self, buf: &mut Vec<u8>) -> IsNull {
+        buf.put_str_lenenc(&self.to_string());
+
+        IsNull::No
+    }
+}
+
+impl Decode<'_, MySql> for Decimal {
+    fn decode(value: MySqlValueRef<'_>) -> Result<Self, BoxDynError> {
+        Ok(value.as_str()?.parse()?)
+    }
+}

sqlx-core/src/mysql/types/mod.rs

@@ -48,6 +48,13 @@
 //! |---------------------------------------|------------------------------------------------------|
 //! | `bigdecimal::BigDecimal`              | DECIMAL                                              |
 //!
+//! ### [`decimal`](https://crates.io/crates/rust_decimal)
+//! Requires the `decimal` Cargo feature flag.
+//!
+//! | Rust type                             | MySQL type(s)                                        |
+//! |---------------------------------------|------------------------------------------------------|
+//! | `rust_decimal::Decimal`               | DECIMAL                                              |
+//!
 //! ### [`json`](https://crates.io/crates/json)
 //!
 //! Requires the `json` Cargo feature flag.
@@ -72,6 +79,9 @@ mod uint;
 #[cfg(feature = "bigdecimal")]
 mod bigdecimal;
 
+#[cfg(feature = "decimal")]
+mod decimal;
+
 #[cfg(feature = "chrono")]
 mod chrono;
 

sqlx-core/src/postgres/types/bigdecimal.rs

@@ -42,7 +42,7 @@ impl TryFrom<PgNumeric> for BigDecimal {
             } => (digits, sign, weight),
 
             PgNumeric::NotANumber => {
-                return Err("BigDecimal does not support NaN values".into());
+                return Err("Decimal does not support NaN values".into());
             }
         };