diff --git a/src/main/java/fr/insee/trevas/lab/utils/Utils.java b/src/main/java/fr/insee/trevas/lab/utils/Utils.java
index 69d199d..5ae2c86 100644
--- a/src/main/java/fr/insee/trevas/lab/utils/Utils.java
+++ b/src/main/java/fr/insee/trevas/lab/utils/Utils.java
@@ -41,7 +41,14 @@ public static ScriptEngine initEngineWithSpark(Bindings bindings, SparkSession s
     public static Bindings getBindings(Bindings input) {
         Bindings output = new SimpleBindings();
         input.forEach((k, v) -> {
-            if (v instanceof PersistentDataset) output.put(k, v);
+            if (!k.startsWith("$")) {
+                if (v instanceof PersistentDataset) {
+                    output.put(k + "$PersistentDataset", v);
+                } else {
+                    output.put(k, v);
+                }
+            }
+            ;
         });
         return output;
     }
@@ -69,17 +76,26 @@ public static SparkConf loadSparkConfig(String stringPath) {
     public static Bindings getSparkBindings(Bindings input, Integer limit) {
         Bindings output = new SimpleBindings();
         input.forEach((k, v) -> {
-            if (v instanceof PersistentDataset) {
-                fr.insee.vtl.model.Dataset ds = ((PersistentDataset) v).getDelegate();
-                if (ds instanceof SparkDataset) {
-                    Dataset<Row> sparkDs = ((SparkDataset) ds).getSparkDataset();
+            if (!k.startsWith("$")) {
+                if ((v instanceof PersistentDataset) || (v instanceof SparkDataset)) {
+                    String name = k;
+                    SparkDataset spDs = null;
+                    if (v instanceof PersistentDataset) {
+                        fr.insee.vtl.model.Dataset ds = ((PersistentDataset) v).getDelegate();
+                        name = name + "$PersistentDataset";
+                        spDs = (SparkDataset) ds;
+                    }
+                    if (v instanceof SparkDataset) {
+                        spDs = (SparkDataset) v;
+                    }
+                    Dataset<Row> sparkDs = (spDs).getSparkDataset();
                     if (limit != null) {
                         SparkDataset sparkDataset = new SparkDataset(sparkDs.limit(limit));
                         InMemoryDataset im = new InMemoryDataset(
                                 sparkDataset.getDataPoints(),
                                 sparkDataset.getDataStructure());
-                        output.put(k, im);
-                    } else output.put(k, new SparkDataset(sparkDs)); // useless
+                        output.put(name, im);
+                    } else output.put(name, new SparkDataset(sparkDs)); // useless
                 }
             }
         });
@@ -90,22 +106,32 @@ public static void writeSparkDatasetsJDBC(Bindings bindings,
                                               Map<String, QueriesForBindingsToSave> queriesForBindingsToSave
     ) {
         queriesForBindingsToSave.forEach((name, values) -> {
-            SparkDataset dataset = (SparkDataset) bindings.get(name);
-            Dataset<Row> dsSpark = dataset.getSparkDataset();
-            String jdbcPrefix = "";
-            try {
-                jdbcPrefix = getJDBCPrefix(values.getDbtype());
-            } catch (Exception e) {
-                e.printStackTrace();
+            Object ds = bindings.get(name);
+            if (!(ds instanceof PersistentDataset)) {
+                try {
+                    throw new Exception(name + " is not a Persistent datatset (affect it with \"<-\")");
+                } catch (Exception e) {
+                    throw new RuntimeException(e);
+                }
+            }
+            fr.insee.vtl.model.Dataset dataset = ((PersistentDataset) bindings.get(name)).getDelegate();
+            if (dataset instanceof SparkDataset) {
+                String jdbcPrefix = "";
+                try {
+                    Dataset<Row> dsSpark = ((SparkDataset) dataset).getSparkDataset();
+                    jdbcPrefix = getJDBCPrefix(values.getDbtype());
+                    dsSpark.write()
+                            .mode(SaveMode.Overwrite)
+                            .format("jdbc")
+                            .option("url", jdbcPrefix + values.getUrl())
+                            .option("dbtable", values.getTable())
+                            .option("user", values.getUser())
+                            .option("password", values.getPassword())
+                            .save();
+                } catch (Exception e) {
+                    e.printStackTrace();
+                }
             }
-            dsSpark.write()
-                    .mode(SaveMode.Overwrite)
-                    .format("jdbc")
-                    .option("url", jdbcPrefix + values.getUrl())
-                    .option("dbtable", values.getTable())
-                    .option("user", values.getUser())
-                    .option("password", values.getPassword())
-                    .save();
         });
     }
 
@@ -113,11 +139,21 @@ public static void writeSparkS3Datasets(Bindings bindings, Map<String, S3ForBind
                                             ObjectMapper objectMapper,
                                             SparkSession spark) {
         s3toSave.forEach((name, values) -> {
-            SparkDataset dataset = (SparkDataset) bindings.get(name);
-            try {
-                writeSparkDataset(objectMapper, spark, values, dataset);
-            } catch (Exception e) {
-                e.printStackTrace();
+            Object ds = bindings.get(name);
+            if (!(ds instanceof PersistentDataset)) {
+                try {
+                    throw new Exception(name + " is not a Persistent datatset (affect it with \"<-\")");
+                } catch (Exception e) {
+                    throw new RuntimeException(e);
+                }
+            }
+            fr.insee.vtl.model.Dataset dataset = ((PersistentDataset) bindings.get(name)).getDelegate();
+            if (dataset instanceof SparkDataset) {
+                try {
+                    writeSparkDataset(objectMapper, spark, values, (SparkDataset) dataset);
+                } catch (Exception e) {
+                    e.printStackTrace();
+                }
             }
         });
     }