check_trig1.sql

这是一个用PB做的学生成绩管理系统

Use xscj
If EXISTS(Select name From sysobjects
         where name='check1_trig' and type='TR')
   DROP TRIGGER check1_trig
GO
CREATE TRIGGER check1_trig
  ON grade
  FOR update
AS
IF EXISTS(Select* 
     FROM inserted a
     WHERE a.stu_id NOT IN(Select b.stu_id FROM stu_info b)OR
     a.cls_id NOT IN(Select c.cls_id FROM course c))
     BEGIN
        RAISERROR('学号或者课程号并不存在!',16,1)
        ROLLBACK TRANSACTION 
     END