Received: from localhost (postgresql.org [64.49.215.8]) by postgresql.org (Postfix) with ESMTP id 2DAEC476B01 for ; Fri, 24 Jan 2003 10:15:06 -0500 (EST) Received: from megazone.bigpanda.com (megazone.bigpanda.com [63.150.15.178]) by postgresql.org (Postfix) with ESMTP id 858BD475F66 for ; Fri, 24 Jan 2003 10:14:07 -0500 (EST) Received: by megazone.bigpanda.com (Postfix, from userid 1001) id A5CAED878; Fri, 24 Jan 2003 07:14:11 -0800 (PST) Received: from localhost (localhost [127.0.0.1]) by megazone.bigpanda.com (Postfix) with ESMTP id 9B1985C1F; Fri, 24 Jan 2003 07:14:11 -0800 (PST) Date: Fri, 24 Jan 2003 07:14:11 -0800 (PST) From: Stephan Szabo To: jack Cc: Subject: Re: quastions about primary key In-Reply-To: <00c301c2c374$1e698650$1400a8c0@jac> Message-ID: <20030124071239.T30220-100000@megazone23.bigpanda.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-Virus-Scanned: by AMaViS new-20020517 X-Archive-Number: 200301/396 X-Sequence-Number: 11261 On Fri, 24 Jan 2003, jack wrote: > Is that possible to have a two columns primary key on a table with null > value on second column? No, because primary key implies not null on all columns involved (technically I think it's that a non-deferrable primary key implies not null on all columns involved, but we don't support deferrable ones)