X-Original-To: pgsql-sql-postgresql.org@postgresql.org Received: from localhost (mx1.hub.org [200.46.208.251]) by postgresql.org (Postfix) with ESMTP id 05F039FC56E for ; Sun, 27 Aug 2006 10:46:52 -0300 (ADT) Received: from postgresql.org ([200.46.204.71]) by localhost (mx1.hub.org [200.46.208.251]) (amavisd-new, port 10024) with ESMTP id 84446-10 for ; Sun, 27 Aug 2006 10:46:45 -0300 (ADT) X-Greylist: from auto-whitelisted by SQLgrey- Received: from wolff.to (wolff.to [66.93.197.194]) by postgresql.org (Postfix) with SMTP id BC05B9FC562 for ; Sun, 27 Aug 2006 10:46:45 -0300 (ADT) Received: (qmail 7709 invoked by uid 500); 27 Aug 2006 13:54:37 -0000 Date: Sun, 27 Aug 2006 08:54:37 -0500 From: Bruno Wolff III To: Richard Broersma Jr Cc: SQL Postgresql List Subject: Re: Create Assertion -- Question from a newbie Message-ID: <20060827135437.GA1869@wolff.to> Mail-Followup-To: Bruno Wolff III , Richard Broersma Jr , SQL Postgresql List References: <20060827071959.57220.qmail@web31810.mail.mud.yahoo.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20060827071959.57220.qmail@web31810.mail.mud.yahoo.com> User-Agent: Mutt/1.4.2.1i X-Virus-Scanned: Maia Mailguard 1.0.1 X-Spam-Status: No, hits=0.028 tagged_above=0 required=5 tests=AWL X-Spam-Level: X-Archive-Number: 200608/207 X-Sequence-Number: 26165 On Sun, Aug 27, 2006 at 00:19:59 -0700, Richard Broersma Jr wrote: > Sorry if my question is a little off topic. > > I am reading my new "SQL for Smarties" book side by side with the PostgreSQL 8.1 manual. I > noticed that this particular feature is not included in PostgreSQL. Some of the achieve threads > mostly discuss that this feature is currently not supported. My understanding is that Assertions > place constraints upon data spanning multiple related tables. > > Is the Assertion feature slated to be added in the future? (Perhaps rolled up in a more > generalized "TO-DO" item?) > > Would this feature add functionality that can not be achieved by other means? (i.e. alternative > schema definitions or triggers?) Or does it merely provide a redundant means to constrain data, > and thereby not warrant addition into the features of PostgreSQL? You can accomplish what assertions do using triggers. I think the issue is generating triggers for general assertions that don't totally suck performancewise.