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 <9 and 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 <触发器名称> { BEFORE | AFTER } { INSERT | UPDATE | DELETE } ON <表名称> FOR EACH ROW <触发器SQL语句> # 删除 DROP TRIGGER <触发器名称> |
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 <9 AND possibility*severity>=4 THEN 2 WHEN possibility*severity <4 THEN 1 END WHERE id = new.id; && CREATE TRIGGER trg_risks_update AFTER UPDATE ON `projectrisk` FOR EACH ROW UPDATE projectrisk SET classification = CASE WHEN possibility*severity>=9 THEN 3 WHEN possibility*severity <9 AND 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 <9 AND new.possibility*new.severity>=4 THEN 2 WHEN new.possibility*new.severity <4 THEN 1 END; END && CREATE TRIGGER trg_risks_update BEFORE UPDATE ON `projectrisk` FOR EACH ROW BEGIN SET new.classification = CASE WHEN new.possibility*new.severity>=9 THEN 3 WHEN new.possibility*new.severity <9 AND 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 BEGININSERT 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 ROWBEGIN 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 ; |
