例如:
有下面五张表,五张表之间都通过主外键关联
Dept(DepId,DepName)Student(StuId,StuName,DepId)Teacher(TeacherId,TeacherName)Course(CourseId,CousreName,TeacherId)Score(CourseID,StuId,Score)现在如果对Dept表中,DepId进行修改或者删除,怎么修改?最好能有代码说明!!!
有下面五张表,五张表之间都通过主外键关联
Dept(DepId,DepName)Student(StuId,StuName,DepId)Teacher(TeacherId,TeacherName)Course(CourseId,CousreName,TeacherId)Score(CourseID,StuId,Score)现在如果对Dept表中,DepId进行修改或者删除,怎么修改?最好能有代码说明!!!
使用触发器又比较麻烦。建议删除以前先做下判断。--例如:
Dept(DepId,DepName)Student(StuId,StuName,DepId)
--删除一个DepIddelete from Dept where DepId=@DepId --传入的变量 (直接这样可以会报错)if(select count(*) from Student where DepId=@DepId )>0
select '存在约束不能删除'
else
delete from Dept where DepId=@DepId
后修改成绩表, update 成绩表 set ID='[正确ID]' where ID='[错误ID]'
就2个update语句而已呀,有什么问题?