Re: Table acting as a relation table

From: Lennart <erik.lennart.jonsson_at_gmail.com>
Date: Wed, 11 Apr 2007 09:03:50 +0200
Message-ID: <evi18m$lqb$1@registered.motzarella.org>

David Cressey wrote:
[...]
> What Marshall said, and also this:
>
> If you make (HOSP_CODE,CLINIC_CODE) the key to the T_HOSPITAL_CLINIC table,
> this would have the effect of preventing the same entry from being entered
> twice into this table.

I also thought this was what the OP meant in his first post. As Bob pointed out, it makes more sence to use CLINIC_CODE alone as the key in T_HOSPITAL_CLINIC.
> This is generally a "good thing". Relations cannot
> have duplicate tuples, by definition. By preventing the table from having
> duplicate rows, you cause the behavior of the table to be more congruent.
>
> I would take your expert's advice to create separate key column for each
> table with a very large grain of salt. I believe that's bad general advice,
> and I think Marshall and Bob are also saying that.
>

Agreed

/Lennart Received on Wed Apr 11 2007 - 02:03:50 CDT