mysql transaction - roll back on any exception - mysql

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 transaction;
insert into myTable values1 ...
insert into myTable values2 ...; -- will throw an error
commit;
now, on execute i want the whole transaction to fail, and therefore i should NOT see values1 in myTable.
but unfortunately the table is being pupulated with values1 even though the transaction has errors.
any ideas how i make it to roll back? (again, on any error)?
EDIT - changed from DDL to standard SQL

Answer 1

You can use 13.6.7.2. DECLARE ... HANDLER Syntax in the following way:
DELIMITER $$
CREATE PROCEDURE `sp_fail`()
BEGIN
DECLARE `_rollback` BOOL DEFAULT 0;
DECLARE CONTINUE HANDLER FOR SQLEXCEPTION SET `_rollback` = 1;
START TRANSACTION;
INSERT INTO `tablea` (`date`) VALUES (NOW());
INSERT INTO `tableb` (`date`) VALUES (NOW());
INSERT INTO `tablec` (`date`) VALUES (NOW()); -- FAIL
IF `_rollback` THEN
ROLLBACK;
ELSE
COMMIT;
END IF;
END$$
DELIMITER ;
For a complete example, check the following SQL Fiddle.

Answer 2

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 ;

Answer 3

The above solution are good but to make it even simpler
DELIMITER $$
CREATE PROCEDURE `sp_fail`()
BEGIN
DECLARE EXIT HANDLER FOR SQLEXCEPTION
BEGIN
ROLLBACK; -- rollback any error in the transaction
END;
START TRANSACTION;
insert into myTable values1 ...
insert into myTable values2 ... -- Fails
COMMIT; -- this will not be executed
END$$
DELIMITER ;