VARIABLES

Translation spec for Package Variables

Description

PACKAGE VARIABLES can be declared either in the package declaration or in the PACKAGE BODY. Due to its behavior, these variables are converted into Snowflake session variables so each usage or assignment is translated to its equivalent in Snowflake.

Oracle Variable declaration syntax

variable datatype [ [ NOT NULL] {:= | DEFAULT} expression ] ;

Sample Source Patterns

Sample auxiliary code

Oracle

IN -> Oracle_01.sql

create table table1(id number);

Snowflake

Variable declaration

Oracle

Query

IN -> Oracle_02.sql

CREATE OR REPLACE PACKAGE PKG1 AS
    package_variable NUMBER:= 100;
END PKG1;

Snowflake Scripting

Query

OUT -> Oracle_02.sql

CREATE SCHEMA IF NOT EXISTS PKG1
COMMENT = '{"origin":"sf_sc","name":"snowconvert","version":{"major":1, "minor":0},{"attributes":{"component":"oracle"}}'
;

SET "PKG1.PACKAGE_VARIABLE" = '' || (100);

Variable Usage

Package variable usages are transformed into the Snowflake GETVARIABLE function which accesses the current value of a session variable. An explicit cast is added to the original variable data type in order to maintain the functional equivalence in the operations where these variables are used.

Oracle

Query

IN -> Oracle_03.sql

CREATE OR REPLACE PACKAGE PKG1 AS
    PROCEDURE procedure1;
    package_variable NUMBER:= 100;
END PKG1;

CREATE OR REPLACE PACKAGE BODY PKG1 AS
    PROCEDURE procedure1 AS
    BEGIN
        INSERT INTO TABLE1(ID) VALUES(package_variable);
    END;
END PKG1;

CALL SCHEMA1.PKG1.procedure1();

SELECT * FROM TABLE1;

Result

Snowflake

Query

OUT -> Oracle_03.sql

CREATE SCHEMA IF NOT EXISTS PKG1
COMMENT = '{"origin":"sf_sc","name":"snowconvert","version":{"major":1, "minor":0},{"attributes":{"component":"oracle"}}'
;

SET "PKG1.PACKAGE_VARIABLE" = '' || (100);

CREATE OR REPLACE PROCEDURE PKG1.procedure1 ()
RETURNS VARCHAR
LANGUAGE SQL
COMMENT = '{"origin":"sf_sc","name":"snowconvert","version":{"major":1, "minor":0},{"attributes":{"component":"oracle"}}'
EXECUTE AS CALLER
AS
$$
    BEGIN
        INSERT INTO TABLE1(ID) VALUES(GETVARIABLE('PKG1.PACKAGE_VARIABLE') :: NUMBER);
    END;
$$;

CALL SCHEMA1.PKG1.procedure1();

SELECT * FROM
    TABLE1;

Result

Note that the PROCEDURE definition in the package is removed since it is not required by Snowflake.

Variable regular assignment

When a package variable is assigned using the := operator, the assignation is replaced by a SnowConvert UDF called UPDATE_PACKAGE_VARIABLE_STATE which is an abstraction of the Snowflake SETVARIABLE function.

Oracle

Query

IN -> Oracle_04.sql

CREATE OR REPLACE PACKAGE PKG1 AS
    PROCEDURE procedure1;
    package_variable NUMBER:= 100;
END PKG1;

CREATE OR REPLACE PACKAGE BODY PKG1 AS
    PROCEDURE procedure1 AS
    BEGIN
        package_variable := package_variable + 100;
        INSERT INTO TABLE1(ID) VALUES(package_variable);
    END;
END PKG1;

CALL PKG1.procedure1();

SELECT * FROM TABLE1;

Result

Snowflake

Query

OUT -> Oracle_04.sql

CREATE SCHEMA IF NOT EXISTS PKG1
COMMENT = '{"origin":"sf_sc","name":"snowconvert","version":{"major":1, "minor":0},{"attributes":{"component":"oracle"}}'
;

SET "PKG1.PACKAGE_VARIABLE" = '' || (100);

CREATE OR REPLACE PROCEDURE PKG1.procedure1 ()
RETURNS VARCHAR
LANGUAGE SQL
COMMENT = '{"origin":"sf_sc","name":"snowconvert","version":{"major":1, "minor":0},{"attributes":{"component":"oracle"}}'
EXECUTE AS CALLER
AS
$$
    BEGIN
        CALL UPDATE_PACKAGE_VARIABLE_STATE_UDF('PKG1.PACKAGE_VARIABLE', TO_VARCHAR(GETVARIABLE('PKG1.PACKAGE_VARIABLE') :: NUMBER + 100));
        INSERT INTO TABLE1(ID) VALUES(GETVARIABLE('PKG1.PACKAGE_VARIABLE') :: NUMBER);
    END;
$$;

CALL PKG1.procedure1();

SELECT * FROM
    TABLE1;

Result

Note that the PROCEDURE definition in the package is removed since it is not required by Snowflake.

Variable assignment as an output argument

When a package variable is used as an output argument a new variable is declared inside the procedure, this variable will catch the output argument value of the procedure, and then the variable will be used to update the session variable which refers to the package variable using the UPDATE_PACKAGE_VARIABLE_STATE mentioned above. For more information check de output parameters transformation.

Oracle

Query

IN -> Oracle_05.sql

CREATE OR REPLACE PACKAGE PKG1 AS
    PROCEDURE procedure1;
    PROCEDURE procedure2(out_param OUT NUMBER);
    package_variable NUMBER:= 100;
END PKG1;

CREATE OR REPLACE PACKAGE BODY PKG1 AS
    PROCEDURE procedure1 AS
    BEGIN
        procedure2(package_variable);
        INSERT INTO TABLE1(ID) VALUES(package_variable);
    END;
    PROCEDURE procedure2 (out_param OUT NUMBER) AS
    BEGIN
        out_param := 1000;
    END;
END PKG1;

CALL PKG1.procedure1();

Result

Snowflake

Query

OUT -> Oracle_05.sql

CREATE SCHEMA IF NOT EXISTS PKG1
COMMENT = '{"origin":"sf_sc","name":"snowconvert","version":{"major":1, "minor":0},{"attributes":{"component":"oracle"}}'
;

SET "PKG1.PACKAGE_VARIABLE" = '' || (100);

CREATE OR REPLACE PROCEDURE PKG1.procedure1 ()
RETURNS VARCHAR
LANGUAGE SQL
COMMENT = '{"origin":"sf_sc","name":"snowconvert","version":{"major":1, "minor":0},{"attributes":{"component":"oracle"}}'
EXECUTE AS CALLER
AS
$$
    DECLARE
        PKG1_PACKAGE_VARIABLE VARIANT;
        call_results VARIANT;
    BEGIN
        call_results := (
            CALL PKG1.
            procedure2(:PKG1_PACKAGE_VARIABLE)
        );
        PKG1_PACKAGE_VARIABLE := :call_results;
        CALL UPDATE_PACKAGE_VARIABLE_STATE_UDF('PKG1.PACKAGE_VARIABLE', TO_VARCHAR(:PKG1_PACKAGE_VARIABLE));
        INSERT INTO TABLE1(ID) VALUES(GETVARIABLE('PKG1.PACKAGE_VARIABLE') :: NUMBER);
    END;
$$;

CREATE OR REPLACE PROCEDURE PKG1.procedure2 (out_param NUMBER(38, 18))
RETURNS VARIANT
LANGUAGE SQL
COMMENT = '{"origin":"sf_sc","name":"snowconvert","version":{"major":1, "minor":0},{"attributes":{"component":"oracle"}}'
EXECUTE AS CALLER
AS
$$
    BEGIN
        out_param := 1000;
        RETURN null;
    END;
$$;

CALL PKG1.procedure1();

Result

Note that the PROCEDURE definition in the package is removed since it is not required by Snowflake.

Known Issues

No issues were found.

Related EWIs

1. MSCEWI1082: Auto-Generated code in order to support output parameters in Snowflake Scripting.

2. MSCEWI3122: Package Variable Assignment transformation.

3. SSC-FDM-0006: Number type column may not behave similarly in Snowflake.

4. SSC-EWI-OR0123: Db Link connections not supported