工作笔记--Mysql触发器使用示例

更新IDC_Device_Info表记录时，记录下修改的时间，存到Device_Last_Modify表中。

DROP TRIGGER IF EXISTS deviceLastUpdate;
CREATE TRIGGER deviceLastUpdate
AFTER UPDATE ON `IDC_Device_Info`
FOR EACH ROW
BEGIN
	BEGIN
		DECLARE cntOld TINYINT DEFAULT 0;
		DECLARE serviceIdOld INT DEFAULT 0;
		DECLARE deviceTypeOld INT DEFAULT 0;

		SET serviceIdOld 	= IFNULL(OLD.Service_ID,0);
		SET deviceTypeOld = IFNULL(OLD.Device_Type,0);

		SELECT COUNT(*) INTO cntOld FROM Device_Last_Modify WHERE Service_ID = serviceIdOld AND Device_Type = deviceTypeOld;
		IF cntOld > 0 THEN
			UPDATE Device_Last_Modify SET Last_Modify = UNIX_TIMESTAMP(NOW()) WHERE Service_ID = serviceIdOld AND Device_Type = deviceTypeOld;
		ELSE
			INSERT INTO Device_Last_Modify VALUES (serviceIdOld, deviceTypeOld, UNIX_TIMESTAMP(NOW()));
		END IF;
	END;

	BEGIN
		DECLARE cntNew TINYINT DEFAULT 0;
		DECLARE serviceIdNew INT DEFAULT 0;
		DECLARE deviceTypeNew INT DEFAULT 0;
		
		SET serviceIdNew 	= IFNULL(NEW.Service_ID,0);
		SET deviceTypeNew = IFNULL(NEW.Device_Type,0);
		
		SELECT COUNT(*) INTO cntNew FROM Device_Last_Modify WHERE Service_ID = serviceIdNew AND Device_Type = deviceTypeNew;
		IF cntNew > 0 THEN
			UPDATE Device_Last_Modify SET Last_Modify = UNIX_TIMESTAMP(NOW()) WHERE Service_ID = serviceIdNew AND Device_Type = deviceTypeNew;
		ELSE
			INSERT INTO Device_Last_Modify VALUES (serviceIdNew, deviceTypeNew, UNIX_TIMESTAMP(NOW()));
		END IF;
	END;
END;