Re: Separate PK in Jxn Tbl?

From: Phil Stanton <phil_at_stantonfamily.co.uk>
Date: Tue, 22 Jan 2008 20:43:54 -0000
Message-ID: <13pclc9bkkveq4e_at_corp.supernews.com>


I always use just the 2 primary keys but.... If I were a library lending 2 undiffentiatable copies of 1 book to the same person, I suppose I would need an Autonumber PK plus A BookID and BorrowerID.

Phil

"Neil" <nospam_at_nospam.net> wrote in message news:6kslj.128$J41.113_at_newssvr14.news.prodigy.net...
> Whenever I've created junction tables in the past, I always made the PK of
> the junction table the combined pks from the two other tables. Ex: Table1
> PK=A; Table2 PK=B; Junction table consists of two fields, A and B, which
> together comprise the PK for the junction table.
>
> However, I just came across some code in which the person created a
> junction table with a separate PK consisting of an autonumber field, and
> then the two fields.
>
> So I was wondering how others did junction tables -- with a standalone
> autonumber PK, or with a PK consisting of the PKs of the tables being
> joined? And, if a standalone PK, then why?
>
> Thanks!
>
> Neil
>
Received on Tue Jan 22 2008 - 21:43:54 CET

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