Question

编写一个数据库触发器,规定他在到达规定的时间时执行DML(即insert,update,delete)任务

比如想让他在16:00 时触发执行

Answer 1

create trigger tr_a
on a
for insert,update,delere as
begin

IF EXISTS(SELECT 1 FROM inserted) AND NOT EXISTS(SELECT 1 FROM deleted)
BEGIN
-- 插入触发.
INSERT INTO B
SELECT
inserted.a
FROM
inserted;
END;

IF EXISTS(SELECT 1 FROM inserted) AND EXISTS(SELECT 1 FROM deleted)
BEGIN
-- 更新触发.
DELETE FROM B WHERE a in ( SELECT a FROM deleted);

INSERT INTO B
SELECT
inserted.a
FROM
inserted;
END;

IF NOT EXISTS(SELECT 1 FROM inserted) AND EXISTS(SELECT 1 FROM deleted)
BEGIN
-- 删除触发
DELETE FROM B WHERE a in ( SELECT a FROM deleted);

END;