mysql 触发器语法与应用示例

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;

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 ;

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 ;

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 ;

希望本文所述对大家MySQL数据库计有所帮助。

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