Re: Foriegn key which could point to multiple tables?

Yep, you've got it! Corresponding rows in both tables contain the same primary key value, and in the dependant table the primary key is also a foriegn key. The example you've given is correct.

"Eric Gibson" <aithien_at_SCREWSPAMearthlink.net> wrote in message news:dHtta.56637$4P1.5228485_at_newsread2.prod.itd.earthlink.net...
>

[snip]
>
> Okay, okay, I've read up and I think I've got it! The only thing I don't
> quite understand is this shared key thing... Is the actual key *value*
the
> same in both tables for a given IsA relationship?
>
> Say I have a table entry in CourseActivities:
>
> CourseActivities(CourseActivityID=1, ActivityOccurence=1,
ActivityChapter=1,
> ActivityCompleteTime=30, ActivityType=1, CourseID=1)
>
> It's the first object to occur (ActivityOccurence) in the Course
(CourseID),
> labeled under chapter one (ActivityChapter), and the person must view it
for
> 30 minutes(ActivityCompleteTime), and it's labeled as a lecture by type
> (ActivityType).
>
> Then I have an entry in my Lecture object table:
>
> Lectures(CourseActivityID=1, LectureName='Basics of Med Term')
>
> In this example CourseActivityID in the Lectures table acts as a foriegn
key
> and primary key simultaneously, right? You're right my entire model
snapped
> together perfectly and it actually fixed quite a few other small
> descrepencies after I made these changes.
>
> Eric
>
>
Received on Mon May 05 2003 - 18:36:46 CEST