1.迁移数据
进行数据库移植，sql server=>mysql。sql server上有如下的trigger
SET QUOTED_IDENTIFIER ON GO SET ANSI_NULLS ON GO ALTER TRIGGER [trg_risks] ON dbo.projectrisk FOR INSERT, UPDATE AS BEGIN UPDATE projectrisk SET classification = case when calc>= 9 then 3 when calc=4 then 2 when calc<4 then 1 end from (select inserted.id, inserted.possibility*inserted.severity as calc from inserted) as T1 where projectrisk.id = T1.id END GO SET QUOTED_IDENTIFIER OFF GO SET ANSI_NULLS ON GO
简单了解了下MySQL中，Trigger的语法。
# 创建
CREATE TRIGGER
{ BEFORE | AFTER }
{ INSERT | UPDATE | DELETE }
ON
FOR EACH ROW
# 删除
DROP TRIGGER
注：创建触发器需要CREATE TRIGGER权限。（HeidiSQL中执行Trigger语句会有bug）
由于MySQL中的每个触发器只能针对一个动作，所以本次移植就需要创建两个触发器。对于发生变更的行，在触发器中可以用 NEW 来代替。
下边的触发器有什么问题吗？
delimiter && CREATE TRIGGER trg_risks_insert AFTER INSERT ON `projectrisk` FOR EACH ROW UPDATE projectrisk SET classification = CASE WHEN possibility*severity>=9 THEN 3 WHEN possibility*severity=4 THEN 2 WHEN possibility*severity=9 THEN 3 WHEN possibility*severity=4 THEN 2 WHEN possibility*severity<4 THEN 1 END WHERE id = new.id; && delimiter ;
问题就是，没有考虑到触发器中的修改也会触发触发器，进入了死循环。做了如下修改后，终于OK了。
delimiter && CREATE TRIGGER trg_risks_insert BEFORE INSERT ON `projectrisk` FOR EACH ROW BEGIN SET new.classification = CASE WHEN new.possibility*new.severity>=9 THEN 3 WHEN new.possibility*new.severity=4 THEN 2 WHEN new.possibility*new.severity=9 THEN 3 WHEN new.possibility*new.severity=4 THEN 2 WHEN new.possibility*new.severity<4 THEN 1 END; END && delimiter ;
2.同步备份数据记录表
添加记录到新记录表
DELIMITER $$ USE `DB_Test`$$ CREATE /*!50017 DEFINER = 'root'@'%' */ TRIGGER `InsertOPM_Alarm_trigger` BEFORE INSERT ON `OPM_Alarm` FOR EACH ROW BEGIN INSERT INTO OPM_Alarm_copy (AlarmId,AlarmCode,AlarmTypeId,AlarmLevelId,AlarmObjectCode,AlarmStatus, AlarmHandleUser, AlarmHandleTime,ADDTIME,ParkUserId,BerthCode,BargainOrderCode,BerthStartTime) VALUES(new.AlarmId,new.AlarmCode,new.AlarmTypeId,new.AlarmLevelId,new.AlarmObjectCode,new.AlarmStatus, new.AlarmHandleUser, new.AlarmHandleTime,new.ADDTIME,new.ParkUserId,new.BerthCode,new.BargainOrderCode,new.BerthStartTime); END; $$ DELIMITER ; CREATE TRIGGER InsertOPM_Alarm_trigger BEFORE INSERT ON OPM_Alarm FOR EACH ROW BEGIN INSERT INTO OPM_Alarm_copy (AlarmId,AlarmCode,AlarmTypeId,AlarmLevelId,AlarmObjectCode,AlarmStatus, AlarmHandleUser, AlarmHandleTime,ADDTIME,ParkUserId,BerthCode,BargainOrderCode,BerthStartTime) VALUES(new.AlarmId,new.AlarmCode,new.AlarmTypeId,new.AlarmLevelId,new.AlarmObjectCode,new.AlarmStatus, new.AlarmHandleUser, new.AlarmHandleTime,new.ADDTIME,new.ParkUserId,new.BerthCode,new.BargainOrderCode,new.BerthStartTime); END ;
mysql触发器监控mysql数据表记录删除操作 DELIMITER $$
USE `DB_Test`$$ DROP TRIGGER /*!50032 IF EXISTS */ `SYS_OPM_trigger`$$ CREATE /*!50017 DEFINER = 'root'@'%' */ TRIGGER `SYS_OPM_trigger` AFTER DELETE ON `OPM_Alarm` FOR EACH ROW BEGIN DECLARE str VARCHAR(40000); SET str=CONCAT(old.AlarmId,'@',old.AlarmCode,'@',old.AlarmTypeId,'@',old.AlarmLevelId,'@', old.AlarmObjectCode,'@',old.AlarmStatus,'@',old.AlarmHandleUser,'@',old.AlarmHandleTime,'@', old.AddTime,'@',old.ParkUserId,'@',old.BerthCode,'@',old.BargainOrderCode,'@',old.BerthStartTime); INSERT INTO OPM_AlarmAction_log(UserName,Client_IP,Delete_before_key,Delete_Date) VALUES(SUBSTRING_INDEX(USER(),'@',1),SUBSTRING_INDEX(USER(),'@',-1), str, NOW()); END; $$ DELIMITER ;
删除前 添加原记录备份到另一记录表
DELIMITER $$
USE `DB_Test`$$
DROP TRIGGER /*!50032 IF EXISTS */ `InsertOPM_Alarm_trigger`$$
CREATE
/*!50017 DEFINER = 'root'@'%' */
TRIGGER `InsertOPM_Alarm_trigger` BEFORE
DELETE ON `OPM_Alarm`
FOR EACH ROW BEGIN
INSERT INTO OPM_Alarm_copy
(AlarmId,AlarmCode,AlarmTypeId,AlarmLevelId,AlarmObjectCode,AlarmStatus,AlarmHandleUser,
AlarmHandleTime,ADDTIME,ParkUserId,BerthCode,BargainOrderCode,BerthStartTime)
VALUES
(old.AlarmId,old.AlarmCode,old.AlarmTypeId,old.AlarmLevelId,old.AlarmObjectCode,old.AlarmS
tatus,old.AlarmHandleUser,
old.AlarmHandleTime,old.ADDTIME,old.ParkUserId,old.BerthCode,old.BargainOrderCode,old.Bert
hStartTime);
END;
$$
DELIMITER ;以上就是MySQL触发器运用于迁移和同步数据的实例教程_MySQL的内容，更多相关内容请关注PHP中文网（www.php.cn）！
