当操作了某张数据表时，希望同时触发一些动作或行为，就可以使用触发器完成。
当操作微博表时，同时生成一条日志记录
-- 插入时触发 create trigger tri_weiboAdd after insert on weibo from each row insert into log(create_time) values(unix_timestamp()) -- 修改时触发 create trigger tri_weiboUpd after update on weibo from each row insert into log(create_time) values(unix_timestamp()) -- 删除时触发 create grigger tri_weiboDel after delete on weibo from each row insert into log(create_time) values(unix_timestamp())
原文：https://www.cnblogs.com/iverson-3/p/10303684.html