Received: from localhost (maia-1.hub.org [200.46.204.191]) by postgresql.org (Postfix) with ESMTP id 96A169FA197 for ; Wed, 18 Apr 2007 09:20:04 -0300 (ADT) Received: from postgresql.org ([200.46.204.71]) by localhost (mx1.hub.org [200.46.204.191]) (amavisd-maia, port 10024) with ESMTP id 39074-08 for ; Wed, 18 Apr 2007 09:19:54 -0300 (ADT) X-Greylist: from auto-whitelisted by SQLgrey-1.7.4 Received: from westnet.com (westnet.com [216.187.52.2]) by postgresql.org (Postfix) with ESMTP id 4970C9FA4B2 for ; Wed, 18 Apr 2007 09:19:54 -0300 (ADT) Received: from westnet.com (localhost [127.0.0.1]) by westnet.com (8.14.0/8.14.0) with ESMTP id l3ICJtaX015936 for ; Wed, 18 Apr 2007 08:19:55 -0400 (EDT) Received: from localhost (gsmith@localhost) by westnet.com (8.14.0/8.13.2/Submit) with ESMTP id l3ICJt5n015933 for ; Wed, 18 Apr 2007 08:19:55 -0400 (EDT) X-Authentication-Warning: westnet.com: gsmith owned process doing -bs Date: Wed, 18 Apr 2007 08:19:55 -0400 (EDT) From: Greg Smith X-X-Sender: gsmith@westnet.com To: pgsql-performance@postgresql.org Subject: Re: Basic Q on superfluous primary keys In-Reply-To: <4625E35C.2060708@archonet.com> Message-ID: References: <20070414075947.e5fbeec8.wmoran@collaborativefusion.com> <46239000.7000708@modgraph-usa.com> <46259937.7030502@modgraph-usa.com> <4625E35C.2060708@archonet.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed X-Virus-Scanned: Maia Mailguard 1.0.1 X-Archive-Number: 200704/329 X-Sequence-Number: 24206 On Wed, 18 Apr 2007, Richard Huxton wrote: > And at the end of the day that's the root of the problem. It's easy to be > lulled into "well it looks like a primary key" rather than being able to > guarantee it. In some of these cases it is guaranteed to be a primary key given all available information at the time. The funny thing about unexpected changes to a business model is that you never expect them. -- * Greg Smith gsmith@gregsmith.com http://www.gregsmith.com Baltimore, MD