check_trig.sql

来自「这是一个用PB做的学生成绩管理系统」· SQL 代码 · 共 20 行

Use xscj
If EXISTS(Select name From sysobjects
         where name='check_trig' and type='TR')
   DROP TRIGGER check_trig
GO
CREATE TRIGGER check_trig
  ON grade
  FOR INSERT
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;