Date: Sun, 21 Jan 2007 10:28:38 -0500
From: Andrew Sullivan <ajs@crankycanuck.ca>
To: pgsql-sql@postgresql.org
Subject: Re: select based on multi-column primary keys
Message-ID: <20070121152838.GB3533@phlogiston.dyndns.org>
References: <45B16602.2080508@furthernorth.net> <eos326$13fv$1@news.hub.org>
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On Fri, Jan 19, 2007 at 07:45:40PM -0800, codeWarrior wrote:
> AFAIK: You cannot have multiple primary keys. How would you know which one 
> is the actual key ?

You can have a multi-column primary key, though.  That's a perfectly
legitimate approach.

> FYI: What you are really talking about are table contraints... When you have 

No, it's a multi-column primary key.

> My advice would be to alter your table structure so that you have a "real" 
> PK not table constraints -- that would make it searchable....

This is already searchable.  What you are talking about is not a real
primary key, but an artificial one.  The OP already has a real
primary key.  SQL purists think artificial primary keys mean that you
haven't done enough normalisation.  I'm going to remain silent on
that topic, though, so that we don't get a Thread That Does Not End
:)

A


-- 
Andrew Sullivan  | ajs@crankycanuck.ca
If they don't do anything, we don't need their acronym.
		--Josh Hamilton, on the US FEMA