mysql transaction - roll back on any exception

Question

Is it possible to roll back automatically if any error occurs on a list of mysql commands?

for example something along the lines of:

begin transactio         


        

Answer 1

You could use EXIT HANDLER if you for example need to SIGNAL a specific SQL EXCEPTION in your code. For instance:

DELIMITER $$

CREATE PROCEDURE `sp_fail`()
BEGIN
    DECLARE EXIT HANDLER FOR SQLEXCEPTION
    BEGIN
        ROLLBACK;  -- rollback any changes made in the transaction
        RESIGNAL;  -- raise again the sql exception to the caller
    END;

    START TRANSACTION;
    insert into myTable values1 ...
    IF fail_condition_meet THEN
        SIGNAL SQLSTATE '45000' SET MESSAGE_TEXT = 'Custom error detected.', MYSQL_ERRNO = 2000;
    END IF;
    insert into myTable values2 ...  -- this will not be executed
    COMMIT; -- this will not be executed
END$$

DELIMITER ;