Re: use triggers to enforce interigity

Boy, are you making a *BIG* assumption!

Alan Shein wrote:
>
> Exactly.
>
> If _you_ can figure everything out _you_ will be an expert. So, start
> figuring. The longest journey begins with but a single step. Give a man a
> fish and he eats for a day, teach a man to fish and he eats always.
>
> We've all been there (learning by "fire"), and even without mentioning that
> a particular problem is a homework assignment, we can usually spot them.
>
> General advice- usually, the assignment is closely related to what was just
> taught or read, so it is often easy to refer back to the most recent
> classroom examples or book examples to find a similar problem that merely
> needs some additional thought and modification. Your professor is not going
> to give you something you can't do alone. Also, don't be afraid to ask the
> professor for help. They are usually happy to offer a hint if you can show
> you thought about it and are stuck. If the professor does not wish to offer
> a hint, it is often because the problem is easier than you thought (which is
> a hint in itself), or you haven't thought about it enough. I suspect that if
> you first try to solve it, and still need help, you could post your _work_
> here and get some advice to steer you in the right direction.
>
> And to twist another saying...
>
> May you have interesting assignments.
>
> Jingyan <jingyan.xu_at_tst2000.com> wrote in message
> news:smA04.1696$LK3.65291_at_nuq-read.news.verio.net...
> > If I can figure everything out, I will be an expert, not a student.
> > Jingyan
> >
> > Kevin O'Gorman wrote in message
> > <3841D1E7.BE0B3248_at_trixie.kosman.via.ayuda.com>...
> > >Jingyan wrote:
> > >>
> > >> Hi,
> > >> My homework assignment is to use triggers to enforce integrity.
> > >> I have student(student_id, student_name),
> course(course_id,course_title),
> > >> and studentCourse(student_id, course_id) tables. each table has a
> > trigger.
> > >> in the trigger of student table, when the student_id is updated, the
> same
> > >> student_id in studentCourse is updated too. the trigger in
> studentCourse
> > >> check if new student_id that will be set in the studentCourse has
> exist
> > in
> > >> the student table. if not, the trigger will be raise a error and give
> up
> > the
> > >> updating.
> > >> But when I update the student_id of student table, I got error. I guess
> I
> > >> should not use my approach to enforce integrity. How to enforce them?
> > >>
> > >> Thank a lot,
> > >>
> > >> Jingyan Xu
> > >
> > >I hope nobody needs reminding not to do someone else's homework. This
> > >student
> > >will learn more by thinking it through.
> > >
> > >
> > >--
> > >Kevin O'Gorman (805) 650-6274 kogorman_at_pacbell.net
> > >At school: kogorman_at_cs.ucsb.edu
> > >Permanent e-mail forwarder: Kevin.O'Gorman.64_at_Alum.Dartmouth.org
> >
> >

--
Quote from Rick Cook, mission manager for NASA's Mars Pathfinder project:

"Programming today is a race between software engineers striving to build bigger and better idiot-proof programs, and the universe trying to produce bigger and better idiots.

So far, the universe is winning." Received on Fri Dec 03 1999 - 18:11:11 CST