Translate MAP ctor and element access to JSONB for Postgres

Author: ferenc-csaky

sqrl-planner/src/main/java/com/datasqrl/function/translation/postgres/builtinflink/MapConstructorSqlTranslation.java

@@ -0,0 +1,42 @@
+/*
+ * Copyright © 2021 DataSQRL (contact@datasqrl.com)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.datasqrl.function.translation.postgres.builtinflink;
+
+import static com.datasqrl.function.CalciteFunctionUtil.lightweightOp;
+
+import com.datasqrl.function.translation.PostgresSqlTranslation;
+import com.datasqrl.function.translation.SqlTranslation;
+import com.google.auto.service.AutoService;
+import org.apache.calcite.sql.SqlCall;
+import org.apache.calcite.sql.SqlWriter;
+import org.apache.calcite.sql.fun.SqlStdOperatorTable;
+import org.apache.calcite.sql.parser.SqlParserPos;
+
+@AutoService(SqlTranslation.class)
+public class MapConstructorSqlTranslation extends PostgresSqlTranslation {
+
+  public MapConstructorSqlTranslation() {
+    super(SqlStdOperatorTable.MAP_VALUE_CONSTRUCTOR);
+  }
+
+  @Override
+  public void unparse(SqlCall call, SqlWriter writer, int leftPrec, int rightPrec) {
+    // Translate MAP['k1', v1, 'k2', v2] to jsonb_build_object('k1', v1, 'k2', v2)
+    lightweightOp("jsonb_build_object")
+        .createCall(SqlParserPos.ZERO, call.getOperandList())
+        .unparse(writer, leftPrec, rightPrec);
+  }
+}

sqrl-planner/src/main/java/com/datasqrl/function/translation/postgres/builtinflink/MapElementSqlTranslation.java

@@ -0,0 +1,62 @@
+/*
+ * Copyright © 2021 DataSQRL (contact@datasqrl.com)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.datasqrl.function.translation.postgres.builtinflink;
+
+import com.datasqrl.function.translation.PostgresSqlTranslation;
+import com.datasqrl.function.translation.SqlTranslation;
+import com.google.auto.service.AutoService;
+import org.apache.calcite.sql.SqlCall;
+import org.apache.calcite.sql.SqlIdentifier;
+import org.apache.calcite.sql.SqlKind;
+import org.apache.calcite.sql.SqlLiteral;
+import org.apache.calcite.sql.SqlWriter;
+import org.apache.calcite.sql.fun.SqlStdOperatorTable;
+import org.apache.calcite.sql.type.SqlTypeName;
+
+@AutoService(SqlTranslation.class)
+public class MapElementSqlTranslation extends PostgresSqlTranslation {
+
+  public MapElementSqlTranslation() {
+    super(SqlStdOperatorTable.ITEM);
+  }
+
+  @Override
+  public void unparse(SqlCall call, SqlWriter writer, int leftPrec, int rightPrec) {
+    if (call.operandCount() == 2) {
+      var baseOperand = call.operand(0);
+      var indexOrKey = call.operand(1);
+
+      var isMapBase =
+          baseOperand instanceof SqlIdentifier
+              || baseOperand.getKind() == SqlKind.MAP_VALUE_CONSTRUCTOR;
+
+      // Heuristic: If the index/key is a string literal, treat as map access
+      // Maps use string keys: map['name'], arrays use numeric indices: array[1]
+      var isLikelyMapAccess =
+          indexOrKey instanceof SqlLiteral literal && literal.getTypeName() == SqlTypeName.CHAR;
+
+      if (isMapBase && isLikelyMapAccess) {
+        // Translate map['key'] to map->>'key' for PostgreSQL JSONB access
+        call.operand(0).unparse(writer, 0, 0);
+        writer.print("->>");
+        call.operand(1).unparse(writer, 0, 0);
+        return;
+      }
+    }
+
+    call.getOperator().unparse(writer, call, leftPrec, rightPrec);
+  }
+}

sqrl-testing/sqrl-testing-integration/src/test/java/com/datasqrl/FullUseCaseIT.java

@@ -49,7 +49,7 @@ public class FullUseCaseIT extends AbstractFullUseCaseTest {
   @Test
   @Disabled("Intended for manual usage")
   void specificUseCase() {
-    var pkg = USE_CASES.resolve("duckdb").resolve("package.json");
+    var pkg = USE_CASES.resolve("function-translation").resolve("postgres").resolve("package.json");
 
     var param = new UseCaseParam(pkg);
     fullUseCaseTest(param);

sqrl-testing/sqrl-testing-integration/src/test/resources/snapshots/com/datasqrl/UseCaseCompileTest/postgres-package.txt

@@ -83,7 +83,7 @@ FunctionCalls := SELECT
 
     ELEMENT(ARRAY[3])                                         AS element_example,
 --     CARDINALITY(MAP['a', 1, 'b', 2])                          AS cardinality_example,
---     MAP['a', 1, 'b', 2]['a']                                  AS map_index_example,
+    MAP['a', 1, 'b', 2]['a']                                  AS map_elem_access_example,
     ARRAY_CONTAINS(ARRAY[1, 2, 3], 2)                         AS array_contains_example,
 --     ARRAY_DISTINCT(ARRAY['a', 'b', 'b', 'c'])                 AS array_distinct_example,
     ARRAY_PREPEND(ARRAY['b', 'c'], 'a')                       AS array_prepend_example,
@@ -141,3 +141,11 @@ ArrayFunctionsTest :=
         ARRAY_POSITION(arrayagg_example, 'y') IS NOT NULL AS array_has_y,
         ARRAY_POSITION(arrayagg_example, 'z') IS NOT NULL AS array_has_z
     FROM ArrayFunctions;
+
+/*+engine(postgres)*/
+_MapData := SELECT MAP['name', name,'city', city] AS map_elems
+            FROM (VALUES ('Alice', 'Berlin'), ('Bob', 'Paris')) AS t(name, city);
+
+/*+test */
+MapTest :=
+    SELECT map_elems['name'] AS elem_name FROM _MapData;

sqrl-testing/sqrl-testing-integration/src/test/resources/usecases/function-translation/postgres/pg-translation.sqrl

@@ -52,6 +52,7 @@
       "is_decimal_example" : true,
       "is_digit_example" : true,
       "element_example" : 3,
+      "map_elem_access_example" : 1,
       "array_contains_example" : true,
       "array_prepend_example" : [ "a", "b", "c" ],
       "array_concat_example" : [ "a", "b", "c", "d", "e" ],

sqrl-testing/sqrl-testing-integration/src/test/resources/usecases/function-translation/postgres/snapshots/FunctionCallsTest.snapshot

@@ -0,0 +1,9 @@
+{
+  "data" : {
+    "MapTest" : [ {
+      "elem_name" : "Alice"
+    }, {
+      "elem_name" : "Bob"
+    } ]
+  }
+}