X-Original-To: pgsql-sql-postgresql.org@localhost.postgresql.org Received: from localhost (unknown [200.46.204.144]) by svr1.postgresql.org (Postfix) with ESMTP id 6127D5E46CF for ; Thu, 19 Aug 2004 13:23:21 -0300 (ADT) Received: from svr1.postgresql.org ([200.46.204.71]) by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024) with ESMTP id 94005-07 for ; Thu, 19 Aug 2004 16:23:28 +0000 (GMT) Received: from davinci.ethosmedia.com (server226.ethosmedia.com [209.128.84.226]) by svr1.postgresql.org (Postfix) with ESMTP id 666055E46CE for ; Thu, 19 Aug 2004 13:23:20 -0300 (ADT) Received: from [63.195.55.98] (HELO spooky) by davinci.ethosmedia.com (CommuniGate Pro SMTP 4.1.8) with ESMTP id 6120795; Thu, 19 Aug 2004 09:24:43 -0700 Content-Type: text/plain; charset="iso-8859-1" From: Josh Berkus Organization: Aglio Database Solutions To: Jan Wieck Subject: Re: multi column foreign key for implicitly unique columns Date: Thu, 19 Aug 2004 09:21:59 -0700 User-Agent: KMail/1.4.3 Cc: pgsql-sql@postgresql.org References: <1092734724.2627.4.camel@dicaprio.akademie1.de> <200408181155.34472.josh@agliodbs.com> <4123D91D.8060601@Yahoo.com> In-Reply-To: <4123D91D.8060601@Yahoo.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Message-Id: <200408190921.59529.josh@agliodbs.com> X-Virus-Scanned: by amavisd-new at hub.org X-Spam-Status: No, hits=0.0 tagged_above=0.0 required=5.0 tests= X-Spam-Level: X-Archive-Number: 200408/219 X-Sequence-Number: 18716 Jan, > Because the value in b.y is redundant. b.x->a.x->a.y is exactly the same > value and he even wants to ensure this with the constraint. And in the absence of that constraint, what ensures that b.y = a.y, exactly? -- Josh Berkus Aglio Database Solutions San Francisco