Re: Separate PK in Jxn Tbl?
Date: Tue, 22 Jan 2008 20:43:54 -0000
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.
"Neil" <nospam_at_nospam.net> wrote in message
> 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?
Received on Tue Jan 22 2008 - 21:43:54 CET