50.9.1. create trigger

实现 history 历史表功能，BEFORE update 做到数据库更新自动备份

CREATE TABLE user_history SELECT * FROM user WHERE 1 <> 1DELIMITER //
CREATE TRIGGER user_history BEFORE update ON user FOR EACH ROW
BEGIN
insert into user_history SELECT * FROM user WHERE id = OLD.id;
END; //
DELIMITER ;

判断某字段数据修改满足条件后出发。

CREATE DEFINER=`dba`@`%` TRIGGER `cms`.`jc_content_BEFORE_UPDATE` BEFORE UPDATE ON `jc_content` FOR EACH ROW
BEGINIF NEW.status = '1' THENinsert into `neo`.elasticsearch_trash(id) values(OLD.content_id);END IF;IF NEW.status = '2' THENdelete from `neo`.elasticsearch_trash where id = OLD.content_id;END IF;
END

CREATE DEFINER=`dba`@`%` TRIGGER `cms`.`jc_content_BEFORE_DELETE` BEFORE DELETE ON `jc_content` FOR EACH ROW
BEGINinsert into `neo`.elasticsearch_trash(id) values(OLD.content_id);
END

50.9.2. drop trigger

50.9.3. show triggers

mysql> SHOW CREATE TRIGGER ins_sum\G
*************************** 1. row ***************************Trigger: ins_sumsql_mode: STRICT_TRANS_TABLES,NO_ENGINE_SUBSTITUTION
SQL Original Statement: CREATE DEFINER=`me`@`localhost` TRIGGER ins_sumBEFORE INSERT ON accountFOR EACH ROW SET @sum = @sum + NEW.amountcharacter_set_client: utf8collation_connection: utf8_general_ciDatabase Collation: latin1_swedish_ciCreated: 2013-07-09 10:39:34.96           

50.9.4. EXAMPLE

CREATE DEFINER=`neo`@`%` TRIGGER `accounts_angelfund` AFTER INSERT ON `accounts` FOR EACH ROW BEGINIF new.paymode = 'angelfund' THENcall angelfund(new.name,new.ctime);        END IF;ENDCREATE DEFINER=`neo`@`%` PROCEDURE `angelfund`(IN `puid` VARCHAR(50), IN `ptime` DATETIME)LANGUAGE SQLNOT DETERMINISTICCONTAINS SQLSQL SECURITY DEFINERCOMMENT ''
BEGINDECLARE fusername VARCHAR(16) DEFAULT NULL;DECLARE fchinese_name VARCHAR(16) DEFAULT NULL;DECLARE fmembers_date VARCHAR(20) DEFAULT NULL;SELECT username,chinese_name,FROM_UNIXTIME(createtime) INTO fusername,fchinese_name,fmembers_date FROM members WHERE username = puid;IF fusername IS NOT NULL THENINSERT IGNORE INTO angelfund(username,chinese_name,members_date,accounts_date,endtime,`status`,op,operator,`description`) value(fusername,fchinese_name,fmembers_date,ptime,DATE_ADD(ptime, INTERVAL +1 MONTH),'N','N','computer','');END IF;END