Received: from localhost (postgresql.org [64.49.215.8]) by postgresql.org (Postfix) with ESMTP id 0DBA7476C1B for ; Fri, 24 Jan 2003 02:32:26 -0500 (EST) Received: from mail3.tpgi.com.au (mail.tpgi.com.au [203.12.160.59]) by postgresql.org (Postfix) with ESMTP id 23341476FAF for ; Fri, 24 Jan 2003 01:45:04 -0500 (EST) Received: from jac (bri-ts2-2600-181.tpgi.com.au [203.219.25.181]) by mail3.tpgi.com.au (8.11.6/8.11.6) with SMTP id h0O6j2R04535 for ; Fri, 24 Jan 2003 17:45:02 +1100 Message-ID: <00c301c2c374$1e698650$1400a8c0@jac> From: "jack" To: Subject: quastions about primary key Date: Fri, 24 Jan 2003 16:44:59 +1000 MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2600.0000 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2600.0000 X-Virus-Scanned: by AMaViS new-20020517 X-Archive-Number: 200301/386 X-Sequence-Number: 11251 Is that possible to have a two columns primary key on a table with null value on second column? Jack