mysql中set autocommit=0与start transaction区别
set autocommit=0指事务非自动提交,自此句执行以后,每个SQL语句或者语句块所在的事务都需要显示"commit"才能提交事务。
1、不管autocommit 是1还是0
START TRANSACTION 后,只有当commit数据才会生效,ROLLBACK后就会回滚。
2、当autocommit 为 0 时
不管有没有START TRANSACTION。
只有当commit数据才会生效,ROLLBACK后就会回滚。
3、如果autocommit 为1 ,并且没有START TRANSACTION 。
调用ROLLBACK是没有用的。即便设置了SAVEPOINT。
回滚成功
set autocommit =1; DELIMITER $$ DROP PROCEDURE IF EXISTS mmmm $$ CREATE DEFINER=`tms_admin`@`%` PROCEDURE `mmmm`() BEGIN DECLARE t_error INTEGER DEFAULT 0; DECLARE CONTINUE HANDLER FOR SQLEXCEPTION,SQLWARNING,NOT FOUND SET t_error=1; START TRANSACTION; SAVEPOINT p1; update t_user set instance_seq_id = 'tt00006'; update t_user set instance_seq_id000 = 'tt00007'; IF t_error = 1 THEN ROLLBACK to p1; ELSE COMMIT; END IF; END$$ DELIMITER ; CALL `tms_inst_tt00003`.`mmmm`();
set autocommit =0; DELIMITER $$ DROP PROCEDURE IF EXISTS mmmm $$ CREATE DEFINER=`tms_admin`@`%` PROCEDURE `mmmm`() BEGIN DECLARE t_error INTEGER DEFAULT 0; DECLARE CONTINUE HANDLER FOR SQLEXCEPTION,SQLWARNING,NOT FOUND SET t_error=1; START TRANSACTION; SAVEPOINT p1; update t_user set instance_seq_id = 'tt00006'; update t_user set instance_seq_id000 = 'tt00007'; IF t_error = 1 THEN ROLLBACK to p1; ELSE COMMIT; END IF; END$$ DELIMITER ; CALL `tms_inst_tt00003`.`mmmm`();
回滚成功
set autocommit =0; DELIMITER $$ DROP PROCEDURE IF EXISTS mmmm $$ CREATE DEFINER=`tms_admin`@`%` PROCEDURE `mmmm`() BEGIN DECLARE t_error INTEGER DEFAULT 0; DECLARE CONTINUE HANDLER FOR SQLEXCEPTION,SQLWARNING,NOT FOUND SET t_error=1; SAVEPOINT p1; update t_user set instance_seq_id = 'tt00006'; update t_user set instance_seq_id000 = 'tt00007'; IF t_error = 1 THEN ROLLBACK to p1; ELSE COMMIT; END IF; END$$ DELIMITER ;
回滚成功