FORALL

Description

The FORALL statement runs one DML statement multiple times, with different values in the VALUES and WHERE clauses. (Oracle PL/SQL Language Reference FORALL Statement).

Oracle Syntax

FORALL index IN bounds_clause [ SAVE ] [ EXCEPTIONS ] dml_statement ;

Snowflake Scripting has no direct equivalence with the FORALL statement, however can be emulated with different workarounds to get functional equivalence.

Sample Source Patterns

Setup Data

Oracle

Tables 1

CREATE TABLE table1 (
    column1 NUMBER,
    column2 NUMBER
);

INSERT INTO table1 (column1, column2) VALUES (1, 2);
INSERT INTO table1 (column1, column2) VALUES (2, 3);
INSERT INTO table1 (column1, column2) VALUES (3, 4);
INSERT INTO table1 (column1, column2) VALUES (4, 5);
INSERT INTO table1 (column1, column2) VALUES (5, 6);

CREATE TABLE table2 (
    column1 NUMBER,
    column2 NUMBER
);

INSERT INTO table2 (column1, column2) VALUES (1, 2);

Tables 2

Snowflake

Tables 1

CREATE OR REPLACE TABLE table1 (
  column1 NUMBER(38, 18) /*** MSC-WARNING - MSCEWI1066 - NUMBER TYPE COLUMN MAY NOT BEHAVE SIMILARLY IN SNOWFLAKE ***/,
  column2 NUMBER(38, 18) /*** MSC-WARNING - MSCEWI1066 - NUMBER TYPE COLUMN MAY NOT BEHAVE SIMILARLY IN SNOWFLAKE ***/
);

INSERT INTO table1(column1, column2) VALUES (1, 2);
INSERT INTO table1(column1, column2) VALUES (2, 3);
INSERT INTO table1(column1, column2) VALUES (3, 4);
INSERT INTO table1(column1, column2) VALUES (4, 5);
INSERT INTO table1(column1, column2) VALUES (5, 6);

CREATE OR REPLACE TABLE table2 (
  column1 NUMBER(38, 18) /*** MSC-WARNING - MSCEWI1066 - NUMBER TYPE COLUMN MAY NOT BEHAVE SIMILARLY IN SNOWFLAKE ***/,
  column2 NUMBER(38, 18) /*** MSC-WARNING - MSCEWI1066 - NUMBER TYPE COLUMN MAY NOT BEHAVE SIMILARLY IN SNOWFLAKE ***/
);

INSERT INTO table2(column1, column2) VALUES (1, 2);

Tables 2

1. FORALL With Collection of Records

Oracle

The three cases below have the same transformation to Snowflake Scripting and are functionally equivalent.

Case 1

CREATE OR REPLACE PROCEDURE myProcedure IS
    CURSOR cursorVariable IS SELECT * FROM table1;
    TYPE tableType IS TABLE OF cursorVariable%ROWTYPE;
    tableVariable tableType;
BEGIN
    OPEN cursorVariable;
    LOOP
        FETCH cursorVariable BULK COLLECT INTO tableVariable LIMIT 100;
        EXIT WHEN tableVariable.COUNT = 0;

        FORALL forIndex IN 1..tableVariable.COUNT
            INSERT INTO table2 (column1, column2)
            VALUES (tableVariable(forIndex).column1, tableVariable(forIndex).column2);
    END LOOP;
    CLOSE cursorVariable;
END;

Case 2

Case 3

Results

Snowflake

FORALL With Collection of Records

CREATE OR REPLACE PROCEDURE myProcedure ()
RETURNS VARCHAR
LANGUAGE SQL
EXECUTE AS CALLER
AS
$$
    BEGIN
        --** MSC-WARNING - MSCCP0005 - THIS STATEMENT HAS USAGES OF CURSOR FETCH BULK OPERATIONS **
        --** MSC-WARNING - MSCCP0006 - FETCH INSIDE A LOOP IS CONSIDERED A COMPLEX PATTERN, THIS COULD DEGRADE SNOWFLAKE PERFORMANCE. **
        INSERT INTO table2(column1, column2)
        (
            SELECT
                column1,
                column2
            FROM
                table1
        );
    END;
$$;

Results

The EWIs MSCCP0005 and MSCCP0006 are added in every FETCH BULK COLLECT occurrence into FORALL statement.

2. FORALL With INSERT INTO

Oracle

FORALL Example

CREATE OR REPLACE PROCEDURE myProcedure IS
    CURSOR cursorVariable IS
        SELECT * FROM table1;
    TYPE collectionTypeDefinition IS TABLE OF table1%ROWTYPE;
    collectionVariable collectionTypeDefinition;
BEGIN
    OPEN cursorVariable;
    LOOP
        FETCH cursorVariable BULK COLLECT INTO collectionVariable limit 2;
        EXIT WHEN collectionVariable.COUNT = 0;
        FORALL forIndex IN collectionVariable.FIRST..collectionVariable.LAST
            INSERT INTO table2 VALUES collectionVariable(forIndex);
        collectionVariable.DELETE;
    END LOOP;
    CLOSE cursorVariable;
END;

Results

Snowflake

FORALL Equivalent

CREATE OR REPLACE PROCEDURE myProcedure ()
RETURNS VARCHAR
LANGUAGE SQL
EXECUTE AS CALLER
AS
$$
    BEGIN
        --** MSC-WARNING - MSCCP0005 - THIS STATEMENT HAS USAGES OF CURSOR FETCH BULK OPERATIONS **
        --** MSC-WARNING - MSCCP0006 - FETCH INSIDE A LOOP IS CONSIDERED A COMPLEX PATTERN, THIS COULD DEGRADE SNOWFLAKE PERFORMANCE. **
        INSERT INTO table2
        (
            SELECT
                * FROM
                table1
        );
    END;
$$;

Results

3. FORALL With Multiple Fetched Collections

Oracle

With INSERT INTO

CREATE OR REPLACE PROCEDURE myProcedure IS
    CURSOR cursorVariable IS
        SELECT * FROM table1;
    column1Collection dbms_sql.NUMBER_table;
    column2Collection dbms_sql.NUMBER_table;
BEGIN
    OPEN cursorVariable;
    LOOP
        FETCH cursorVariable BULK COLLECT INTO column1Collection, column2Collection limit 20;
        EXIT WHEN column1Collection.COUNT = 0;
        FORALL forIndex IN 1..column1Collection.COUNT
            INSERT INTO table2 VALUES (
                column1Collection(forIndex),
                column2Collection(forIndex)
            );
    END LOOP;
    CLOSE cursorVariable;
END;

With UPDATE

Results INSERT INTO

Results UPDATE

Snowflake

With INSERT INTO

CREATE OR REPLACE PROCEDURE myProcedure ()
RETURNS VARCHAR
LANGUAGE SQL
EXECUTE AS CALLER
AS
$$
    BEGIN
        --** MSC-WARNING - MSCCP0005 - THIS STATEMENT HAS USAGES OF CURSOR FETCH BULK OPERATIONS **
        --** MSC-WARNING - MSCCP0006 - FETCH INSIDE A LOOP IS CONSIDERED A COMPLEX PATTERN, THIS COULD DEGRADE SNOWFLAKE PERFORMANCE. **
        INSERT INTO table2
        (
            SELECT
                $1,
                $2
            FROM
                table1
        );
    END;
$$;

With UPDATE

Results INSERT INTO

Results UPDATE

4. FORALL With Record of Collections

Oracle

FORALL Example

CREATE OR REPLACE PROCEDURE myProcedure IS
    CURSOR cursorVariable IS
        SELECT * FROM table1;
    TYPE recordType IS RECORD(
        column1Collection dbms_sql.NUMBER_table,
        column2Collection dbms_sql.NUMBER_table
    );
    columnRecord recordType;
BEGIN
    OPEN cursorVariable;
    LOOP
        FETCH cursorVariable BULK COLLECT INTO columnRecord.column1Collection, columnRecord.column2Collection limit 20;
        FORALL forIndex IN 1..columnRecord.column1Collection.COUNT
            INSERT INTO table2 VALUES (
                columnRecord.column1Collection(forIndex),
                columnRecord.column2Collection(forIndex)
            );
        EXIT WHEN cursorVariable%NOTFOUND;
    END LOOP;
    CLOSE cursorVariable;
END;

Results

Snowflake

Scripting FORALL Equivalent

CREATE OR REPLACE PROCEDURE myProcedure ()
RETURNS VARCHAR
LANGUAGE SQL
EXECUTE AS CALLER
AS
$$
    BEGIN
        --** MSC-WARNING - MSCCP0005 - THIS STATEMENT HAS USAGES OF CURSOR FETCH BULK OPERATIONS **
        --** MSC-WARNING - MSCCP0006 - FETCH INSIDE A LOOP IS CONSIDERED A COMPLEX PATTERN, THIS COULD DEGRADE SNOWFLAKE PERFORMANCE. **
        INSERT INTO table2
        (
            SELECT
                $1,
                $2
            FROM
                table1
        );
    END;
$$;

Results

5. FORALL With Dynamic SQL

Oracle

FORALL Example

CREATE OR REPLACE PROCEDURE myProcedure IS
    cursorVariable SYS_REFCURSOR;
    TYPE collectionTypeDefinition IS
        TABLE OF table1%ROWTYPE;
    collectionVariable collectionTypeDefinition;
    query VARCHAR(200) := 'SELECT * FROM table1';
BEGIN
    OPEN cursorVariable FOR query;
    LOOP
        FETCH cursorVariable BULK COLLECT INTO collectionVariable;
        EXIT WHEN collectionVariable.COUNT = 0;
        FORALL forIndex IN collectionVariable.FIRST..collectionVariable.LAST
            INSERT INTO table2 VALUES collectionVariable(forIndex);
        collectionVariable.DELETE;
    END LOOP;
    CLOSE cursorVariable;
END;

Results

Snowflake

FORALL Equivalent

CREATE OR REPLACE PROCEDURE myProcedure ()
RETURNS VARCHAR
LANGUAGE SQL
EXECUTE AS CALLER
AS
$$
    DECLARE
        query VARCHAR(200) := 'SELECT * FROM table1';
    BEGIN
        --** MSC-WARNING - MSCCP0005 - THIS STATEMENT HAS USAGES OF CURSOR FETCH BULK OPERATIONS **
        --** MSC-WARNING - MSCCP0006 - FETCH INSIDE A LOOP IS CONSIDERED A COMPLEX PATTERN, THIS COULD DEGRADE SNOWFLAKE PERFORMANCE. **
        --** MSC-ERROR - MSCCP0004 - THE STATEMENT BELOW HAS USAGES OF DYNAMIC SQL. **
        EXECUTE IMMEDIATE 'CREATE OR REPLACE TEMPORARY TABLE query AS ' || :query;
        INSERT INTO table2
        (
            SELECT
                *
            FROM
                query
        );
    END;
$$;

Results

6. FORALL With Literal SQL

Oracle

FORALL Example

CREATE OR REPLACE PROCEDURE 
IS
    TYPE TabRecType IS RECORD (
        column1 NUMBER,
        column2 NUMBER
    );
    TYPE tabType IS TABLE OF TabRecType;
    cursorRef SYS_REFCURSOR;
    tab tabType;
BEGIN
    OPEN cursorRef FOR 'SELECT src.column1, src.column2 FROM ' || 'table1' || ' src';

    LOOP
        BEGIN
            FETCH cursorRef BULK COLLECT INTO tab LIMIT 1000;
            FORALL i IN 1..tab.COUNT
                INSERT INTO table2 (column1, column2)
                VALUES (tab(i).column1, tab(i).column2);

            EXIT WHEN cursorRef%NOTFOUND;
        END;
    END LOOP;

    CLOSE cursorRef;
END;

Results

Snowflake

FORALL Equivalent

CREATE OR REPLACE PROCEDURE myProcedure ()
RETURNS VARCHAR
LANGUAGE SQL
EXECUTE AS CALLER
AS
$$

    BEGIN
        EXECUTE IMMEDIATE 'CREATE OR REPLACE TEMPORARY TABLE cursorRef_TEMP_TABLE AS ' || 'SELECT src.column1, src.column2 FROM ' || 'table1' || ' src';
        --** MSC-WARNING - MSCCP0005 - THIS STATEMENT HAS USAGES OF CURSOR FETCH BULK OPERATIONS **
        --** MSC-WARNING - MSCCP0006 - FETCH INSIDE A LOOP IS CONSIDERED A COMPLEX PATTERN, THIS COULD DEGRADE SNOWFLAKE PERFORMANCE. **
        INSERT INTO table2(column1, column2)
        (
            SELECT
                *
            FROM
                cursorRef_TEMP_TABLE
        );
    END;
$$;

Results

7. FORALL With Parametrized Cursors

Oracle

FORALL Example

CREATE OR REPLACE PROCEDURE myProcedure IS
    intVariable INTEGER := 7;
    CURSOR cursorVariable(param1 INTEGER, param2 INTEGER default 5) IS
        SELECT * FROM table1
        WHERE
            column2 = intVariable OR
            column1 BETWEEN param1 AND param2;
    TYPE collectionTypeDefinition IS
        TABLE OF table1%ROWTYPE;
    collectionVariable collectionTypeDefinition;
BEGIN
    OPEN cursorVariable(1);
    LOOP
        FETCH cursorVariable BULK COLLECT INTO collectionVariable limit 20;
        EXIT WHEN collectionVariable.COUNT = 0;
        FORALL forIndex IN collectionVariable.FIRST..collectionVariable.LAST
            INSERT INTO table2 VALUES collectionVariable(forIndex);
        collectionVariable.DELETE;
    END LOOP;
    CLOSE cursorVariable;
END;

Results

Snowflake

FORALL Equivalent

CREATE OR REPLACE PROCEDURE myProcedure ()
RETURNS VARCHAR
LANGUAGE SQL
EXECUTE AS CALLER
AS
$$
    DECLARE
        intVariable INTEGER := 7;
    BEGIN
        --** MSC-WARNING - MSCCP0005 - THIS STATEMENT HAS USAGES OF CURSOR FETCH BULK OPERATIONS **
        --** MSC-WARNING - MSCCP0006 - FETCH INSIDE A LOOP IS CONSIDERED A COMPLEX PATTERN, THIS COULD DEGRADE SNOWFLAKE PERFORMANCE. **
        INSERT INTO table2
        (
            SELECT
                * FROM
                table1
                    WHERE
                        column2 = :intVariable
                OR
                        column1 BETWEEN 1 AND 5
        );
    END;
$$;

Results

8. FORALL Without LOOPS

Oracle

FORALL Example

CREATE OR REPLACE PROCEDURE  myProcedure IS
    TYPE collectionTypeDefinition IS TABLE OF table1%ROWTYPE;
    collectionVariable collectionTypeDefinition;
BEGIN
    SELECT * BULK COLLECT INTO collectionVariable FROM table1;
        FORALL forIndex IN 1..collectionVariable.COUNT
            INSERT INTO table2 VALUES (
                collectionVariable (forIndex).column1,
                collectionVariable (forIndex).column2
            );
        collectionVariable.DELETE;
END;

Results

Snowflake

FORALL Equivalent

CREATE OR REPLACE PROCEDURE myProcedure ()
RETURNS VARCHAR
LANGUAGE SQL
EXECUTE AS CALLER
AS
$$
    BEGIN
        --** MSC-WARNING - MSCCP0006 - FETCH INSIDE A LOOP IS CONSIDERED A COMPLEX PATTERN, THIS COULD DEGRADE SNOWFLAKE PERFORMANCE. **
        INSERT INTO table2
        (
            SELECT
                column1,
                column2
            FROM
                table1
        );
    END;
$$;

Results

9. FORALL With UPDATE Statements

Oracle

FORALL Example

CREATE OR REPLACE PROCEDURE myProcedure IS
    CURSOR cursorVariable IS
        SELECT * FROM table1;
    TYPE collectionTypeDefinition IS TABLE OF table1%ROWTYPE;
    collectionVariable collectionTypeDefinition;
BEGIN
    OPEN cursorVariable;
    LOOP
        FETCH cursorVariable BULK COLLECT INTO collectionVariable limit 2;
        EXIT WHEN collectionVariable.COUNT = 0;
        FORALL forIndex IN collectionVariable.FIRST..collectionVariable.LAST
            UPDATE table2 SET column1 = '54321' WHERE column2 = collectionVariable(forIndex).column2;
        collectionVariable.DELETE;
    END LOOP;
    CLOSE cursorVariable;
END;

Results

Snowflake

FORALL Equivalent

CREATE OR REPLACE PROCEDURE myProcedure ()
RETURNS VARCHAR
LANGUAGE SQL
EXECUTE AS CALLER
AS
$$
    BEGIN
        --** MSC-WARNING - MSCCP0005 - THIS STATEMENT HAS USAGES OF CURSOR FETCH BULK OPERATIONS **
        --** MSC-WARNING - MSCCP0006 - FETCH INSIDE A LOOP IS CONSIDERED A COMPLEX PATTERN, THIS COULD DEGRADE SNOWFLAKE PERFORMANCE. **
        UPDATE table2
            SET column1 = '54321'
        FROM (
            SELECT * FROM table1
        ) AS collectionVariable
        WHERE table2.column2 = collectionVariable.column2;
    END;
$$;

Results

10. FORALL With DELETE Statements

Oracle

FORALL Example

CREATE OR REPLACE PROCEDURE myProcedure IS
    CURSOR cursorVariable IS
        SELECT * FROM table1;
    TYPE collectionTypeDefinition IS TABLE OF table1%ROWTYPE;
    collectionVariable collectionTypeDefinition;
BEGIN
    OPEN cursorVariable;
    LOOP
        FETCH cursorVariable BULK COLLECT INTO collectionVariable limit 2;
        EXIT WHEN collectionVariable.COUNT = 0;
        FORALL forIndex IN collectionVariable.FIRST..collectionVariable.LAST
            DELETE FROM table2 WHERE column2 = collectionVariable(forIndex).column2;
        collectionVariable.DELETE;
    END LOOP;
    CLOSE cursorVariable;
END;

Results

Snowflake

FORALL Equivalent

CREATE OR REPLACE PROCEDURE myProcedure ()
RETURNS VARCHAR
LANGUAGE SQL
EXECUTE AS CALLER
AS
$$
    BEGIN
        --** MSC-WARNING - MSCCP0005 - THIS STATEMENT HAS USAGES OF CURSOR FETCH BULK OPERATIONS **
        --** MSC-WARNING - MSCCP0006 - FETCH INSIDE A LOOP IS CONSIDERED A COMPLEX PATTERN, THIS COULD DEGRADE SNOWFLAKE PERFORMANCE. **
        DELETE FROM table2
        USING (
            SELECT * FROM table1
        ) collectionVariable
        WHERE
            table2.column2 = collectionVariable.column2;
    END;
$$;

Results

11. FORALL With PACKAGE References

Oracle

FORALL Example

CREATE OR REPLACE PACKAGE MyPackage AS
    TYPE collectionTypeDefinition IS
        TABLE OF table1%ROWTYPE;
    collectionVariable collectionTypeDefinition;
END;
/
 
CREATE OR REPLACE PROCEDURE InsertIntoPackage(param integer) IS
BEGIN
    SELECT
        param,
        param BULK COLLECT INTO MyPackage.collectionVariable
    FROM
        DUAL;
END;
/
 
CREATE OR REPLACE PROCEDURE InsertUsingPackage IS
BEGIN
        FORALL forIndex IN MyPackage.collectionVariable.FIRST..MyPackage.collectionVariable.LAST
            INSERT INTO table2 VALUES MyPackage.collectionVariable(forIndex);
        MyPackage.collectionVariable.DELETE;
END;
/

DECLARE
    param_value INTEGER := 10;
BEGIN
    InsertIntoPackage(param_value);
    InsertUsingPackage;
END;

select * from table2;

Results

Snowflake

FORALL Equivalent

CREATE SCHEMA IF NOT EXISTS MyPackage;

--   --** MSC-ERROR - MSCEWI3049 - PACKAGE TYPE DEFINITIONS in stateful package MyPackage are not supported yet **
--   TYPE collectionTypeDefinition IS
--        TABLE OF table1%ROWTYPE;

CREATE OR REPLACE TEMPORARY TABLE MYPACKAGE_COLLECTIONVARIABLE (
    column1 NUMBER,
    column2 NUMBER
);

CREATE OR REPLACE PROCEDURE InsertIntoPackage (param integer)
RETURNS VARCHAR
LANGUAGE SQL
EXECUTE AS CALLER
AS
$$
    BEGIN
        DELETE FROM
            MYPACKAGE_COLLECTIONVARIABLE;
        INSERT INTO MYPACKAGE_COLLECTIONVARIABLE
        (
            SELECT
                :param,
                :param
            FROM
    DUAL
        );
    END;
$$;

CREATE OR REPLACE PROCEDURE InsertUsingPackage ()
RETURNS VARCHAR
LANGUAGE SQL
EXECUTE AS CALLER
AS
$$

    BEGIN
        --** MSC-WARNING - MSCCP0006 - FETCH INSIDE A LOOP IS CONSIDERED A COMPLEX PATTERN, THIS COULD DEGRADE SNOWFLAKE PERFORMANCE. **
        INSERT INTO table2
        (
            SELECT
                *
            FROM
                MYPACKAGE_COLLECTIONVARIABLE
        );
    END;
$$;

call InsertIntoPackage(10);
call InsertUsingPackage();
select * from table2;

Results

The transformation above only works if the variable defined in the package is a record of collections.

12. FORALL With MERGE Statements

Oracle

FORALL Example

CREATE OR REPLACE PROCEDURE myProcedure IS
    CURSOR cursorVariable IS
        SELECT * FROM table1;
    TYPE collectionTypeDefinition IS
        TABLE OF table1%ROWTYPE;
    collectionVariable collectionTypeDefinition;
BEGIN
    OPEN cursorVariable;
    LOOP
        FETCH cursorVariable BULK COLLECT INTO collectionVariable limit 2;
        EXIT WHEN collectionVariable.COUNT = 0;
        FORALL forIndex IN collectionVariable.FIRST..collectionVariable.LAST
        MERGE INTO table2 tgt
            USING (
                SELECT
                    collectionVariable(forIndex).column1 column1,
                    collectionVariable(forIndex).column2 column2
                FROM DUAL
            ) src
           ON (tgt.column1 = src.column1)
        WHEN MATCHED THEN
            UPDATE SET
               tgt.column2 = src.column2 * 2
        WHEN NOT MATCHED THEN
            INSERT (column1, column2)
            VALUES (src.column1, src.column2);
    END LOOP;
    CLOSE cursorVariable;
END;

Results

Snowflake

FORALL Equivalent

CREATE OR REPLACE PROCEDURE myProcedure ()
RETURNS VARCHAR
LANGUAGE SQL
EXECUTE AS CALLER
AS
$$
    BEGIN
        --** MSC-WARNING - MSCCP0005 - THIS STATEMENT HAS USAGES OF CURSOR FETCH BULK OPERATIONS **
        --** MSC-WARNING - MSCCP0006 - FETCH INSIDE A LOOP IS CONSIDERED A COMPLEX PATTERN, THIS COULD DEGRADE SNOWFLAKE PERFORMANCE. **
        MERGE INTO table2 tgt
            USING (
            SELECT
                collectionVariable.column1 column1,
                collectionVariable.column2 column2
            FROM (
                SELECT * FROM table1
            ) collectionVariable) src
            ON (tgt.column1 = src.column1)
        WHEN MATCHED THEN
            UPDATE SET tgt.column2 = src.column2 * 2
        WHEN NOT MATCHED THEN
            INSERT (column1, column2)
            VALUES (src.column1, src.column2);
    END;
$$;

Results

The transformation above only works if the SELECT statement inside the MERGE is selecting from DUAL table.

13. Default FORALL transformation

You might also be interested in Bulk Cursor Helpers.

Oracle

FORALL Example

CREATE OR REPLACE PROCEDURE myProcedure IS
    CURSOR cursorVariable IS SELECT * FROM table1;
    TYPE columnsRecordType IS RECORD (column1 dbms_sql.NUMBER_table, column2 dbms_sql.NUMBER_table);
    recordVariable columnsRecordType;
    TYPE collectionTypeDefinition IS TABLE OF table1%ROWTYPE;
    collectionVariable collectionTypeDefinition;
    col1 dbms_sql.NUMBER_table;
    col2 dbms_sql.NUMBER_table;
BEGIN
    OPEN cursorVariable;
    FETCH cursorVariable BULK COLLECT INTO collectionVariable limit 2;
    FORALL forIndex IN collectionVariable.FIRST..collectionVariable.LAST
        INSERT INTO table2 (column1, column2)
        VALUES (collectionVariable(forIndex).column1, collectionVariable(forIndex).column2);

    FETCH cursorVariable BULK COLLECT INTO col1, col2 limit 2;
    FORALL forIndex IN col1.FIRST..col1.LAST
        INSERT INTO table2 (column1, column2)
        VALUES (col1(forIndex), col2(forIndex));

    LOOP
        FETCH cursorVariable BULK COLLECT INTO recordVariable limit 2;
        EXIT WHEN recordVariable.column1.COUNT = 0;
        FORALL forIndex IN recordVariable.column1.FIRST..recordVariable.column1.LAST
            INSERT INTO table2 (column1, column2)
            VALUES (recordVariable.column1(forIndex), recordVariable.column2(forIndex));
    END LOOP;
    CLOSE cursorVariable;
END;

Results

Snowflake

FORALL Equivalent

CREATE OR REPLACE PROCEDURE myProcedure ()
RETURNS VARCHAR
LANGUAGE SQL
EXECUTE AS CALLER
AS
$$
    DECLARE
        cursorVariable OBJECT := INIT_CURSOR('cursorVariable', '   SELECT * FROM table1');
--           --** MSC-WARNING - MSCEWI1056 - CUSTOM TYPES ARE NOT SUPPORTED IN SNOWFLAKE BUT REFERENCES TO THIS CUSTOM TYPE WERE CHANGED TO OBJECT **
--              TYPE columnsRecordType IS RECORD (
--           COLUMN1 VARIANT /*** MSC-WARNING - MSCEWI3125 - BUILT-IN PACKAGE'S CUSTOM TYPE 'dbms_sql.NUMBER_table' CHANGED TO VARIANT ***/,
--           COLUMN2 VARIANT /*** MSC-WARNING - MSCEWI3125 - BUILT-IN PACKAGE'S CUSTOM TYPE 'dbms_sql.NUMBER_table' CHANGED TO VARIANT ***/)
                                                                                                                                      ;
          recordVariable OBJECT /*** MSC-WARNING - MSCEWI1036 - columnsRecordType DATA TYPE CONVERTED TO OBJECT ***/ := OBJECT_CONSTRUCT();
--           --** MSC-ERROR - MSCEWI1058 - FUNCTIONALITY FOR 'PL COLLECTION TYPE DEFINITION' IS NOT CURRENTLY SUPPORTED BY SNOWFLAKE SCRIPTING **
--              TYPE collectionTypeDefinition IS TABLE OF table1%ROWTYPE;
          collectionVariable VARIANT /*** MSC-WARNING - MSCEWI1062 - CUSTOM TYPE 'collectionTypeDefinition' USAGE CHANGED TO VARIANT ***/;
          col1 VARIANT /*** MSC-WARNING - MSCEWI3125 - BUILT-IN PACKAGE'S CUSTOM TYPE 'dbms_sql.NUMBER_table' CHANGED TO VARIANT ***/;
          col2 VARIANT /*** MSC-WARNING - MSCEWI3125 - BUILT-IN PACKAGE'S CUSTOM TYPE 'dbms_sql.NUMBER_table' CHANGED TO VARIANT ***/;
        FORALL INTEGER;
    BEGIN
        cursorVariable := (
            CALL OPEN_BULK_CURSOR(:cursorVariable)
        );
        --** MSC-WARNING - MSCCP0005 - THIS STATEMENT HAS USAGES OF CURSOR FETCH BULK OPERATIONS **
        cursorVariable := (
            CALL FETCH_BULK_COLLECTION_RECORDS(:cursorVariable, 2)
        );
        collectionVariable := :cursorVariable:RESULT;
        FORALL := ARRAY_SIZE(:collectionVariable);
        INSERT INTO table2(column1, column2)
        (
            SELECT
                :collectionVariable[forIndex]:column1,
                : collectionVariable[forIndex]:column2
            FROM (
                SELECT
                    seq4() AS forIndex
                FROM
                    TABLE(GENERATOR(ROWCOUNT => :FORALL))
            )
        );
        --** MSC-WARNING - MSCCP0005 - THIS STATEMENT HAS USAGES OF CURSOR FETCH BULK OPERATIONS **
        cursorVariable := (
            CALL FETCH_BULK_COLLECTIONS(:cursorVariable, 2)
        );
        col1 := :cursorVariable:RESULT[0];
        col2 := :cursorVariable:RESULT[1];
        FORALL := ARRAY_SIZE(:col1);
        INSERT INTO table2(column1, column2)
        (
            SELECT
                :col1[forIndex],
                : col2[forIndex]
            FROM (
                SELECT
                    seq4() AS forIndex
                FROM
                    TABLE(GENERATOR(ROWCOUNT => :FORALL))
            )
        );
        LOOP
            --** MSC-WARNING - MSCCP0006 - FETCH INSIDE A LOOP IS CONSIDERED A COMPLEX PATTERN, THIS COULD DEGRADE SNOWFLAKE PERFORMANCE. **
            --** MSC-WARNING - MSCCP0005 - THIS STATEMENT HAS USAGES OF CURSOR FETCH BULK OPERATIONS **
            cursorVariable := (
                CALL FETCH_BULK_RECORD_COLLECTIONS(:cursorVariable, 2)
            );
            recordVariable := :cursorVariable:RESULT;
            IF (ARRAY_SIZE(:recordVariable:column1) = 0) THEN
                EXIT;
            END IF;
            FORALL := ARRAY_SIZE(:recordVariable:column1);
            INSERT INTO table2(column1, column2)
            (
                SELECT
                    :recordVariable:column1[forIndex],
                    : recordVariable:column2[forIndex]
                FROM (
                    SELECT
                        seq4() AS forIndex
                    FROM
                        TABLE(GENERATOR(ROWCOUNT => :FORALL))
                )
            );
        END LOOP;
        cursorVariable := (
            CALL CLOSE_BULK_CURSOR(:cursorVariable)
        );
    END;
$$;

Results

This transformation is done only when none of the previously mentioned transformations can be done.

14. Multiple FORALL inside a LOOP clause

This pattern applies when there is more than one FORALL in the same procedure and it meets the following structure.

Oracle

FORALL Example

CREATE OR REPLACE PROCEDURE myProcedure IS
    CURSOR cursorVariable IS
        SELECT * FROM table1;

    TYPE collectionTypeDefinition IS TABLE OF table1%ROWTYPE;
    collectionVariable collectionTypeDefinition;
BEGIN
    OPEN cursorVariable;
    LOOP
        FETCH cursorVariable BULK COLLECT INTO collectionVariable limit 20;
        EXIT WHEN collectionVariable.COUNT = 0;

        FORALL forIndex IN collectionVariable.FIRST..collectionVariable.LAST
            INSERT INTO table2 VALUES collectionVariable(forIndex);
        
        FORALL forIndex IN collectionVariable.FIRST..collectionVariable.LAST
            UPDATE table2 SET column1 = '54321' WHERE column2 = collectionVariable(forIndex).column2;

    END LOOP;
    CLOSE cursorVariable;
END;

Results

Snowflake

FORALL Equivalent

CREATE OR REPLACE PROCEDURE myProcedure ()
RETURNS VARCHAR
LANGUAGE SQL
EXECUTE AS CALLER
AS
$$

       BEGIN
           --** MSC-WARNING - MSCCP0005 - THIS STATEMENT HAS USAGES OF CURSOR FETCH BULK OPERATIONS **
           --** MSC-WARNING - MSCCP0006 - FETCH INSIDE A LOOP IS CONSIDERED A COMPLEX PATTERN, THIS COULD DEGRADE SNOWFLAKE PERFORMANCE. **
           INSERT INTO table2
           (
               SELECT
                   * FROM
                   table1
           );
           --** MSC-WARNING - MSCCP0006 - FETCH INSIDE A LOOP IS CONSIDERED A COMPLEX PATTERN, THIS COULD DEGRADE SNOWFLAKE PERFORMANCE. **
           UPDATE table2
               SET column1 = '54321'
               FROM
                   (
                       SELECT
                           * FROM
                           table1) AS collectionVariable
               WHERE table2.column2 = collectionVariable.column2;
       END;
$$;

Results

15. Multiple FORALL inside different LOOP clauses

This pattern applies when there is more than one FORALL in the same procedure and it meets the following structure.

Oracle

FORALL Example

CREATE OR REPLACE PROCEDURE myProcedure IS
    CURSOR cursorVariable IS
        SELECT * FROM table1;

    CURSOR cursorVariable2 IS
        SELECT * FROM table1;

    TYPE collectionTypeDefinition IS
        TABLE OF table1%ROWTYPE;
    collectionVariable collectionTypeDefinition;

    TYPE collectionTypeDefinition2 IS
        TABLE OF table1%ROWTYPE;
    collectionVariable2 collectionTypeDefinition2;
BEGIN
    OPEN cursorVariable;
    LOOP
        FETCH cursorVariable BULK COLLECT INTO collectionVariable limit 2;
        EXIT WHEN collectionVariable.COUNT = 0;
        FORALL forIndex IN collectionVariable.FIRST..collectionVariable.LAST
            INSERT INTO table2 VALUES collectionVariable(forIndex);
    END LOOP;
    CLOSE cursorVariable;

    OPEN cursorVariable2;
    LOOP
        FETCH cursorVariable2 BULK COLLECT INTO collectionVariable2 limit 2;
        EXIT WHEN collectionVariable2.COUNT = 0;
        FORALL forIndex IN collectionVariable2.FIRST..collectionVariable2.LAST
            UPDATE table2 SET column1 = '54321' WHERE column2 = collectionVariable2(forIndex).column2;
    END LOOP;
    CLOSE cursorVariable2;
END;

Results

Snowflake

FORALL Equivalent

CREATE OR REPLACE PROCEDURE myProcedure ()
RETURNS VARCHAR
LANGUAGE SQL
EXECUTE AS CALLER
AS
$$

       BEGIN
           --** MSC-WARNING - MSCCP0005 - THIS STATEMENT HAS USAGES OF CURSOR FETCH BULK OPERATIONS **
           --** MSC-WARNING - MSCCP0006 - FETCH INSIDE A LOOP IS CONSIDERED A COMPLEX PATTERN, THIS COULD DEGRADE SNOWFLAKE PERFORMANCE. **
           INSERT INTO table2
           (
               SELECT
                   * FROM
                   table1
           );
           --** MSC-WARNING - MSCCP0005 - THIS STATEMENT HAS USAGES OF CURSOR FETCH BULK OPERATIONS **
           --** MSC-WARNING - MSCCP0006 - FETCH INSIDE A LOOP IS CONSIDERED A COMPLEX PATTERN, THIS COULD DEGRADE SNOWFLAKE PERFORMANCE. **
           UPDATE table2
               SET column1 = '54321'
               FROM
                   (
                       SELECT
                           * FROM
                           table1) AS collectionVariable2
               WHERE table2.column2 = collectionVariable2.column2;
       END;
$$;

Results

16. FORALL with MERGE INTO with LOG ERRORS

This pattern is not yet implemmented

Oracle

LOG ERRORS

CREATE OR REPLACE PROCEDURE procedure_example (
    department_id_in   IN source_table.DepartmentID%TYPE)
IS
    TYPE employee_ids_t IS TABLE OF source_table%ROWTYPE
    INDEX BY PLS_INTEGER; 
    employee_list   employee_ids_t;
BEGIN
    SELECT *
        BULK COLLECT INTO employee_list
        FROM source_table
        WHERE DepartmentID = procedure_example.department_id_in;
    
    FORALL indx IN 1 .. employee_list.COUNT
      MERGE INTO target_table 
      USING (SELECT * FROM DUAL) src
      ON (id = employee_list(indx).id)
      WHEN MATCHED THEN
        UPDATE SET
          name = employee_list(indx).Name
      WHEN NOT MATCHED THEN
        INSERT (Id, Name, DepartmentID)
        VALUES (employee_list(indx).Id, employee_list(indx).Name, employee_list(indx).DepartmentID)
      LOG ERRORS INTO error_table('MERGE INTO ERROR') 
      REJECT LIMIT UNLIMITED;
        
END;

CALL procedure_example(10);

select * from target_table;
select * from error_table;

Results

Snowflake

LOG ERRORS

--Generated by SnowConvert---------------
CREATE OR REPLACE TRANSIENT TABLE target_staging_table(
  Id INT PRIMARY KEY,
  Name VARCHAR2(10) NOT NULL,
  DepartmentID INT REFERENCES parent_table(Id)
);
--Generated by SnowConvert---------------

CREATE OR REPLACE PROCEDURE procedure_example (DEPARTMENT_ID_IN INT /*** MSC-WARNING - MSCEWI3129 - TYPE ATTRIBUTE 'employees.DepartmentID%TYPE' COULD NOT BE RESOLVED, SO IT WAS TRANSFORMED TO VARIANT ***/)
RETURNS VARCHAR
LANGUAGE SQL
EXECUTE AS CALLER
AS
$$  
    BEGIN
        CREATE OR REPLACE TEMP TABLE SOURCE_TEMPORAL AS
        WITH source_data as (
            SELECT *
            FROM source_table
            WHERE DEPARTMENTID =: DEPARTMENT_ID_IN
        )
        SELECT source_data.*, parent_table.id as PARENT_KEY 
        FROM source_data 
        left join parent_table on source_data.DepartmentID = parent_table.id;
        
        --All records violating foreign key integrity
        INSERT INTO error_table (ERROR, COLUMN_NAME, REJECTED_RECORD)
        SELECT 
            'Foreign Key Constraint Violated' ERROR,'KEY_COL' COLUMN_NAME, id
        FROM SOURCE_TEMPORAL 
        WHERE PARENT_KEY IS NULL;


        DELETE FROM SOURCE_TEMPORAL 
        WHERE PARENT_KEY IS NULL;

        BEGIN
            MERGE INTO target_table
            USING SOURCE_TEMPORAL SRC
            ON SRC.id = target_table.id
            WHEN MATCHED THEN
                UPDATE SET 
                    name = SRC.name
            WHEN NOT MATCHED THEN
               INSERT (Id, Name, DepartmentID)
               VALUES (SRC.Id, SRC.Name, SRC.DepartmentID);
        EXCEPTION
            WHEN OTHER THEN
                CREATE OR REPLACE TEMPORARY STAGE my_int_stage
                  COPY_OPTIONS = (ON_ERROR='continue');
                
                --Create my file and populate with data
                COPY INTO @my_int_stage/my_file FROM (
                SELECT  * exclude(PARENT_KEY) FROM SOURCE_TEMPORAL
                ) OVERWRITE = TRUE ;

                COPY INTO target_staging_table(id, name, DepartmentID) 
                FROM (
                  SELECT 
                    -- distinct
                    t.$1, t.$2, t.$3 
                  FROM @my_int_stage/my_file t
                  ) ON_ERROR = CONTINUE;

                INSERT INTO ERROR_TABLE (ERROR, FILE, LINE, CHARACTER, CATEGORY, CODE, SQL_STATE, COLUMN_NAME, ROW_NUMBER, REJECTED_RECORD)
                SELECT 
                    ERROR, FILE,LINE, CHARACTER, CATEGORY, CODE, SQL_STATE, COLUMN_NAME, ROW_NUMBER, REJECTED_RECORD
                FROM TABLE(VALIDATE(target_staging_table, JOB_ID => '_last')) order by line; --The last charge on the current session

                MERGE INTO target_table
                USING target_staging_table staging
                ON staging.id = target_table.id
                WHEN MATCHED THEN
                    UPDATE SET 
                        name = staging.name
                WHEN NOT MATCHED THEN
                INSERT (Id, Name, DepartmentID)
                VALUES (staging.Id, staging.Name, staging.DepartmentID);
        END;

        return 'Awesome!';
    END;
$$;

CALL procedure_example(10);

SELECT * FROM target_table;
SELECT * FROM error_table;

Results

17. FORALL with INSERT with LOG ERRORS

This pattern is not yet implemmented

Oracle

LOG ERRORS

CREATE OR REPLACE PROCEDURE procedure_example (
    department_id_in   IN source_table.DepartmentID%TYPE)
IS
    TYPE employee_ids_t IS TABLE OF source_table%ROWTYPE
    INDEX BY PLS_INTEGER; 
    employee_list   employee_ids_t;
BEGIN
    SELECT *
        BULK COLLECT INTO employee_list
        FROM source_table
        WHERE DepartmentID = procedure_example.department_id_in;
    
    FORALL indx IN 1 .. employee_list.COUNT
        INSERT INTO target_table(Id, Name, DepartmentID)
        VALUES (employee_list(indx).Id, employee_list(indx).Name, employee_list(indx).DepartmentID)
        LOG ERRORS INTO error_table('MERGE INTO ERROR') 
        REJECT LIMIT UNLIMITED;
END;

Results

Snowflake

LOG ERRORS

--Generated by SnowConvert---------------
CREATE OR REPLACE TRANSIENT TABLE target_staging_table(
  Id INT PRIMARY KEY,
  Name VARCHAR2(10) NOT NULL,
  DepartmentID INT REFERENCES parent_table(Id)
);
--Generated by SnowConvert---------------

CREATE OR REPLACE PROCEDURE procedure_example (DEPARTMENT_ID_IN INT /*** MSC-WARNING - MSCEWI3129 - TYPE ATTRIBUTE 'employees.DepartmentID%TYPE' COULD NOT BE RESOLVED, SO IT WAS TRANSFORMED TO VARIANT ***/)
RETURNS VARCHAR
LANGUAGE SQL
EXECUTE AS CALLER
AS
$$  
    BEGIN
        CREATE OR REPLACE TEMP TABLE SOURCE_TEMPORAL AS
        WITH source_data as (
            SELECT *
            FROM source_table
            WHERE DEPARTMENTID =: DEPARTMENT_ID_IN
        )
        SELECT source_data.*, parent_table.id as PARENT_KEY 
        FROM source_data 
        left join parent_table on source_data.DepartmentID = parent_table.id;
        
        --All records violating foreign key integrity
        INSERT INTO error_table (ERROR, COLUMN_NAME, REJECTED_RECORD)
        SELECT 
            'Foreign Key Constraint Violated' ERROR,'KEY_COL' COLUMN_NAME, id
        FROM SOURCE_TEMPORAL 
        WHERE PARENT_KEY IS NULL;


        DELETE FROM SOURCE_TEMPORAL 
        WHERE PARENT_KEY IS NULL;

        BEGIN
            INSERT INTO target_table (Id, Name, DepartmentID)
            SELECT SRC.Id, SRC.Name, SRC.DepartmentID FROM SOURCE_TEMPORAL SRC;
        EXCEPTION
            WHEN OTHER THEN
                CREATE OR REPLACE TEMPORARY STAGE my_int_stage
                  COPY_OPTIONS = (ON_ERROR='continue');
                
                --Create my file and populate with data
                COPY INTO @my_int_stage/my_file FROM (
                SELECT  * exclude(PARENT_KEY) FROM SOURCE_TEMPORAL
                ) OVERWRITE = TRUE ;

                COPY INTO target_staging_table(id, name, DepartmentID) 
                FROM (
                  SELECT 
                    -- distinct
                    t.$1, t.$2, t.$3 
                  FROM @my_int_stage/my_file t
                  ) ON_ERROR = CONTINUE;

                INSERT INTO ERROR_TABLE (ERROR, FILE, LINE, CHARACTER, CATEGORY, CODE, SQL_STATE, COLUMN_NAME, ROW_NUMBER, REJECTED_RECORD)
                SELECT 
                    ERROR, FILE,LINE, CHARACTER, CATEGORY, CODE, SQL_STATE, COLUMN_NAME, ROW_NUMBER, REJECTED_RECORD
                FROM TABLE(VALIDATE(target_staging_table, JOB_ID => '_last')) order by line; --The last charge on the current session

                INSERT INTO target_table (Id, Name, DepartmentID)
                SELECT staging.Id, staging.Name, staging.DepartmentID FROM target_staging_table staging;
        END;
    END;
$$;

CALL procedure_example(10);

SELECT * FROM target_table;
SELECT * FROM error_table;

Results

Related EWIs

1. MSCCP0004: This statement has usages of dynamic SQL.

2. MSCCP0005: This statement has usages of cursor fetch bulk operations.

3. MSCCP0006: Fetch inside a loop is considered a complex pattern, this could degrade Snowflake performance.