本文实例讲述了MySQL 触发器语法与应用。分享给大家供大家参考，具体如下：
例子：创建触发器，记录表的增、删、改操作记录
//创建user表； DROP TABLE IF EXISTS `user`; CREATE TABLE `user` ( `id` bigint(20) NOT NULL AUTO_INCREMENT, `account` varchar(255) DEFAULT NULL, `name` varchar(255) DEFAULT NULL, `address` varchar(255) DEFAULT NULL, PRIMARY KEY (`id`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8; //创建对user表操作历史表 DROP TABLE IF EXISTS `user_history`; CREATE TABLE `user_history` ( `id` bigint(20) NOT NULL AUTO_INCREMENT, `user_id` bigint(20) NOT NULL, `operatetype` varchar(200) NOT NULL, `operatetime` datetime NOT NULL, PRIMARY KEY (`id`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8;
DELIMITER：改变输入的结束符，默认情况下输入结束符是分号;，这里把它改成了两个分号;;，这样做的目的是把多条含分号的语句做个封装，全部输入完之后一起执行，而不是一遇到默认的分号结束符就自动执行；
- new：当触发插入和更新事件时可用，指向的是被操作的记录
- old： 当触发删除和更新事件时可用，指向的是被操作的记录
INSERT:
DROP TRIGGER IF EXISTS `tri_insert_user`; DELIMITER ;; CREATE TRIGGER `tri_insert_user` AFTER INSERT ON `user` FOR EACH ROW begin INSERT INTO user_history(user_id, operatetype, operatetime) VALUES (new.id, 'add a user', now()); end ;; DELIMITER ;
UPDATE:
DROP TRIGGER IF EXISTS `tri_update_user`; DELIMITER ;; CREATE TRIGGER `tri_update_user` AFTER UPDATE ON `user` FOR EACH ROW begin INSERT INTO user_history(user_id,operatetype, operatetime) VALUES (new.id, 'update a user', now()); end ;; DELIMITER ;
DELETE:
DROP TRIGGER IF EXISTS `tri_delete_user`; DELIMITER ;; CREATE TRIGGER `tri_delete_user` AFTER DELETE ON `user` FOR EACH ROW begin INSERT INTO user_history(user_id, operatetype, operatetime) VALUES (old.id, 'delete a user', now()); end ;; DELIMITER ;
