SnowConvert AI - IBM DB2 - EXIT HANDLER¶

Description¶

An EXIT handler terminates the current compound statement when the specified condition occurs. When a condition occurs and an exit handler is invoked, control is passed to the handler. When the handler completes, control returns to the caller of the compound statement.

In IBM DB2, the DECLARE EXIT HANDLER statement is used to define actions that should be taken when specific SQL conditions or errors occur during procedure execution. Unlike CONTINUE handlers, EXIT handlers terminate the execution of the current block and return control to the caller.

When migrating from DB2 to Snowflake, SnowConvert AI transforms EXIT HANDLER declarations into equivalent Snowflake Scripting exception handling using EXCEPTION blocks with WHEN OTHER EXIT THEN or specific exception types.

For more information about DB2 condition handlers, see IBM DB2 DECLARE HANDLER.

Grammar Syntax¶

DECLARE EXIT HANDLER FOR condition_value [, ...]
  handler_action_statement;

-- Where condition_value can be:
-- SQLSTATE [VALUE] sqlstate_value
-- condition_name
-- SQLWARNING
-- SQLEXCEPTION
-- NOT FOUND

Sample Source Patterns¶

DECLARE EXIT HANDLER FOR SQLEXCEPTION¶

The most common use case is handling SQL exceptions and exiting the current block.

Input Code:¶

IBM DB2¶

CREATE PROCEDURE error_exit_handler()
LANGUAGE SQL
BEGIN
    DECLARE EXIT HANDLER FOR SQLEXCEPTION
    BEGIN
        INSERT INTO error_log VALUES (CURRENT_TIMESTAMP, 'Error occurred, exiting');
    END;
    
    -- These statements may cause errors
    INSERT INTO table1 VALUES (1/0);
    UPDATE table2 SET status = 'completed' WHERE id = -1;
    
    -- This will NOT execute if an error occurred above
    INSERT INTO success_log VALUES ('All operations completed');
END;

Output Code:¶

Snowflake¶

CREATE OR REPLACE PROCEDURE error_exit_handler()
RETURNS VARCHAR
LANGUAGE SQL
COMMENT = '{ "origin": "sf_sc", "name": "snowconvert", "version": {  "major": 0,  "minor": 0,  "patch": "0" }, "attributes": {  "component": "db2",  "convertedOn": "01/15/2025" }}'
AS
$$
    BEGIN
        -- These statements may cause errors
        INSERT INTO table1 VALUES (1/0);
        UPDATE table2 SET status = 'completed' WHERE id = -1;
        
        -- This will NOT execute if an error occurred above
        INSERT INTO success_log VALUES ('All operations completed');
        
        EXCEPTION
            WHEN OTHER THEN
                BEGIN
                    INSERT INTO error_log VALUES (CURRENT_TIMESTAMP(), 'Error occurred, exiting');
                END;
    END;
$$;

DECLARE EXIT HANDLER FOR SQLSTATE¶

Handling specific SQLSTATE codes with exit behavior.

Input Code:¶

IBM DB2¶

CREATE PROCEDURE sqlstate_exit_handler()
LANGUAGE SQL
BEGIN
    DECLARE EXIT HANDLER FOR SQLSTATE '23505'
    BEGIN
        INSERT INTO error_log VALUES ('Duplicate key error, exiting procedure');
        ROLLBACK;
    END;
    
    -- Attempt to insert records
    INSERT INTO users VALUES (1, 'John');
    INSERT INTO users VALUES (1, 'Jane');  -- Duplicate key - will trigger handler
    INSERT INTO users VALUES (2, 'Bob');   -- Will NOT execute
END;

Output Code:¶

Snowflake¶

CREATE OR REPLACE PROCEDURE sqlstate_exit_handler()
RETURNS VARCHAR
LANGUAGE SQL
COMMENT = '{ "origin": "sf_sc", "name": "snowconvert", "version": {  "major": 0,  "minor": 0,  "patch": "0" }, "attributes": {  "component": "db2",  "convertedOn": "01/15/2025" }}'
AS
$$
    BEGIN
        -- Attempt to insert records
        INSERT INTO users VALUES (1, 'John');
        INSERT INTO users VALUES (1, 'Jane');  -- Duplicate key - will trigger handler
        INSERT INTO users VALUES (2, 'Bob');   -- Will NOT execute
        
        EXCEPTION
            WHEN OTHER EXIT THEN
                CASE
                    WHEN (SQLSTATE = '23505') THEN
                        BEGIN
                            INSERT INTO error_log VALUES ('Duplicate key error, exiting procedure');
                            ROLLBACK;
                        END;
                END;
    END;
$$;

DECLARE EXIT HANDLER FOR NOT FOUND¶

The NOT FOUND condition is commonly used with cursors and SELECT INTO statements.

Input Code:¶

IBM DB2¶

CREATE PROCEDURE cursor_exit_handler()
LANGUAGE SQL
BEGIN
    DECLARE v_id INT;
    DECLARE v_name VARCHAR(100);
    
    DECLARE EXIT HANDLER FOR NOT FOUND
        INSERT INTO log_table VALUES ('No data found, exiting');
    
    -- This will trigger the handler if no rows found
    SELECT id, name INTO v_id, v_name 
    FROM employees 
    WHERE department = 'NonExistent';
    
    -- This will NOT execute if no rows were found
    INSERT INTO results VALUES (v_id, v_name);
END;

Output Code:¶

Snowflake¶

CREATE OR REPLACE PROCEDURE cursor_exit_handler()
RETURNS VARCHAR
LANGUAGE SQL
COMMENT = '{ "origin": "sf_sc", "name": "snowconvert", "version": {  "major": 0,  "minor": 0,  "patch": "0" }, "attributes": {  "component": "db2",  "convertedOn": "01/15/2025" }}'
AS
$$
    DECLARE
        v_id INT;
        v_name VARCHAR(100);
    BEGIN
        -- This will trigger the handler if no rows found
        SELECT id, name INTO v_id, v_name 
        FROM employees 
        WHERE department = 'NonExistent';
        
        -- This will NOT execute if no rows were found
        INSERT INTO results VALUES (v_id, v_name);
        
        EXCEPTION
            WHEN NO_DATA_FOUND THEN
                INSERT INTO log_table VALUES ('No data found, exiting');
    END;
$$;

Multiple EXIT Handlers¶

DB2 allows multiple EXIT HANDLERs with different priorities. In Snowflake, handler precedence must be managed through explicit conditional logic using CASE statements.

Input Code:¶

IBM DB2¶

CREATE PROCEDURE multiple_exit_handlers()
BEGIN
    DECLARE EXIT HANDLER FOR SQLSTATE '23505'
        INSERT INTO log VALUES ('Duplicate key error');
    
    DECLARE EXIT HANDLER FOR SQLEXCEPTION
        INSERT INTO log VALUES ('General SQL exception');
    
    INSERT INTO table1 VALUES (1, 'test');
    INSERT INTO success_log VALUES ('Completed');
END;

Output Code:¶

Snowflake¶

CREATE OR REPLACE PROCEDURE multiple_exit_handlers()
RETURNS VARCHAR
LANGUAGE SQL
COMMENT = '{ "origin": "sf_sc", "name": "snowconvert", "version": {  "major": 0,  "minor": 0,  "patch": "0" }, "attributes": {  "component": "db2",  "convertedOn": "01/15/2025" }}'
AS
$$
    BEGIN
        INSERT INTO table1 VALUES (1, 'test');
        INSERT INTO success_log VALUES ('Completed');
        
        EXCEPTION
            WHEN OTHER EXIT THEN
                CASE
                    WHEN (SQLSTATE = '23505') THEN
                        INSERT INTO log VALUES ('Duplicate key error')
                    ELSE
                        INSERT INTO log VALUES ('General SQL exception')
                END;
    END;
$$;

Known Issues¶

EXIT HANDLER Behavior¶

Applies to

IBM DB2

Description¶

EXIT HANDLER in DB2 terminates the current compound statement and returns control to the caller. In Snowflake, this is achieved using the EXCEPTION block, which automatically exits the current BEGIN…END block when an exception occurs.

The main behavioral differences are:

Execution Termination: Both DB2 and Snowflake exit the current block when an EXIT handler is triggered.
Statement-level Control: In DB2, the EXIT handler activates at the statement that causes the error. In Snowflake, the entire remaining block is skipped.
Nested Blocks: Exit behavior in nested blocks is consistent between DB2 and Snowflake.

Mixed CONTINUE and EXIT Handlers¶

Applies to

IBM DB2

Description¶

DB2 allows declaring both CONTINUE and EXIT handlers in the same procedure block. However, Snowflake Scripting does not support mixing CONTINUE and EXIT handlers in the same EXCEPTION block. When this pattern is encountered, SnowConvert AI generates separate EXCEPTION blocks with an EWI warning.

See the CONTINUE HANDLER documentation for detailed examples of this limitation.

Input Code:¶

IBM DB2¶

CREATE OR REPLACE PROCEDURE with_continueAndExit()
BEGIN
    DECLARE test_1 INTEGER DEFAULT 10;
    DECLARE CONTINUE HANDLER FOR SQLEXCEPTION 
        INSERT INTO error_test VALUES ('EXCEPTION');
    DECLARE EXIT HANDLER FOR SQLSTATE '20000' 
        INSERT INTO error_test VALUES ('ERROR 2000');
    
    SET test_1 = 1 / 0;
    INSERT INTO error_test VALUES ('COMPLETED');
END;

Output Code:¶

Snowflake¶

CREATE OR REPLACE PROCEDURE with_continueAndExit()
RETURNS VARCHAR
LANGUAGE SQL
COMMENT = '{ "origin": "sf_sc", "name": "snowconvert", "version": {  "major": 0,  "minor": 0,  "patch": "0" }, "attributes": {  "component": "db2",  "convertedOn": "01/15/2025" }}'
AS
$$
    DECLARE
        test_1 INTEGER DEFAULT 10;
    BEGIN
        test_1 := 1 / 0;
        INSERT INTO error_test VALUES ('COMPLETED');
        EXCEPTION
            WHEN OTHER CONTINUE THEN
                INSERT INTO error_test VALUES ('EXCEPTION')
        !!!RESOLVE EWI!!! /*** SSC-EWI-0114 - MIXED CONTINUE AND EXIT EXCEPTION HANDLERS IN THE SAME BLOCK ARE NOT SUPPORTED BY SNOWFLAKE SCRIPTING ***/!!!
        EXCEPTION
            WHEN OTHER EXIT THEN
                CASE
                    WHEN (SQLSTATE = '20000') THEN
                        INSERT INTO error_test VALUES ('ERROR 2000')
                END
    END;
$$;

Related EWIs¶

SSC-EWI-0114: MIXED CONTINUE AND EXIT EXCEPTION HANDLERS IN THE SAME BLOCK ARE NOT SUPPORTED BY SNOWFLAKE SCRIPTING

SQLSTATE Mapping¶

Not all DB2 SQLSTATE codes have direct equivalents in Snowflake. SnowConvert AI performs best-effort mapping:


DB2 SQLSTATE	Condition	Snowflake Equivalent
02000	NOT FOUND	NO_DATA_FOUND
23xxx	Integrity Constraint Violation	STATEMENT_ERROR
42xxx	Syntax Error	STATEMENT_ERROR
01xxx	Warning	OTHER

Best Practices¶

When working with converted EXIT HANDLER code:

Understand Exit Behavior: EXIT handlers terminate the current block. Ensure your application logic accounts for this behavior.
Test Error Scenarios: Thoroughly test all error conditions to verify that the EXIT handler behaves as expected.
Use Transactions: Leverage Snowflake’s transaction support to ensure data consistency when errors cause early exits.
Logging: Implement comprehensive logging in exception handlers to track when and why procedures exit early.
Nested Blocks: When using nested blocks, understand that EXIT handlers only exit the current block, not the entire procedure.
Return Values: Consider setting return values or output parameters in exception handlers to indicate the reason for exit.

SnowConvert AI - IBM DB2 - EXIT HANDLER¶

Description¶

Grammar Syntax¶

Sample Source Patterns¶

DECLARE EXIT HANDLER FOR SQLEXCEPTION¶

Input Code:¶

IBM DB2¶

Output Code:¶

Snowflake¶

DECLARE EXIT HANDLER FOR SQLSTATE¶

Input Code:¶

IBM DB2¶

Output Code:¶

Snowflake¶

DECLARE EXIT HANDLER FOR NOT FOUND¶

Input Code:¶

IBM DB2¶

Output Code:¶

Snowflake¶

Multiple EXIT Handlers¶

Input Code:¶

IBM DB2¶

Output Code:¶

Snowflake¶

Known Issues¶

EXIT HANDLER Behavior¶

Description¶

Related EWIs¶

Mixed CONTINUE and EXIT Handlers¶

Description¶

Input Code:¶

IBM DB2¶

Output Code:¶

Snowflake¶

Related EWIs¶

SQLSTATE Mapping¶

Best Practices¶

Related Documentation¶

See Also¶