建立一个触发器,当向sc表中添加数据时,如果添加的数据与student表中的数据不匹配(没有对应的学号),则将此数据删除。
CREATE TRIGGER sc_ins ON sc
FOR INSERT AS BEGIN
DECLARE @bh char(5)
Select @bh=Inserted.sno from Inserted
If not exists(select sno from student where student.sno=@bh)
Delete from sc where sno=@bh END