Return-Path: X-Original-To: apmail-db-derby-user-archive@www.apache.org Delivered-To: apmail-db-derby-user-archive@www.apache.org Received: from mail.apache.org (hermes.apache.org [140.211.11.3]) by minotaur.apache.org (Postfix) with SMTP id 0AAEF11D37 for ; Mon, 19 May 2014 16:33:22 +0000 (UTC) Received: (qmail 24184 invoked by uid 500); 19 May 2014 16:33:21 -0000 Delivered-To: apmail-db-derby-user-archive@db.apache.org Received: (qmail 24156 invoked by uid 500); 19 May 2014 16:33:21 -0000 Mailing-List: contact derby-user-help@db.apache.org; run by ezmlm Precedence: bulk list-help: list-unsubscribe: List-Post: List-Id: Reply-To: "Derby Discussion" Delivered-To: mailing list derby-user@db.apache.org Received: (qmail 24149 invoked by uid 99); 19 May 2014 16:33:21 -0000 Received: from nike.apache.org (HELO nike.apache.org) (192.87.106.230) by apache.org (qpsmtpd/0.29) with ESMTP; Mon, 19 May 2014 16:33:21 +0000 X-ASF-Spam-Status: No, hits=-0.7 required=5.0 tests=RCVD_IN_DNSWL_LOW,SPF_PASS X-Spam-Check-By: apache.org Received-SPF: pass (nike.apache.org: domain of john.foreign@gmail.com designates 209.85.212.177 as permitted sender) Received: from [209.85.212.177] (HELO mail-wi0-f177.google.com) (209.85.212.177) by apache.org (qpsmtpd/0.29) with ESMTP; Mon, 19 May 2014 16:33:16 +0000 Received: by mail-wi0-f177.google.com with SMTP id f8so4496809wiw.4 for ; Mon, 19 May 2014 09:32:53 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=message-id:date:from:user-agent:mime-version:to:subject:references :in-reply-to:content-type:content-transfer-encoding; bh=UO/7oBHUpcUdNALPeT/OnxcPmscN5VXualppVmUIJrg=; b=YaA+/f/aEcYh9bLa5QEts2yvMrolXrEisOb66wCDBVPuCB6mF85mrxLA9kcDZNdgd+ Hw8+uhO4yETZKT/5GUYgPPyek22CwP1qyw5SzYq1m6zFpkd0dTQMeMsn6dtUk63T8uEG 9suQJ6wfP/xme+idTnZxxKPNfDq3JV+zdvquws8x5EnGh7i9pbp86hylzPG01KMODCLK pS2j5NPhHO+FCJB9UrC9VerM8Qiz212yVbE//67BgFmbfEImpRNz1I44qYV/IiVdGUcu 97RQt9ky+1kgHJvysmReEut5yKw4xPikGHRk0EvMFms0hprAxSI34x+nWDDpnNP/hYab /xZQ== X-Received: by 10.194.81.164 with SMTP id b4mr31081453wjy.2.1400517173764; Mon, 19 May 2014 09:32:53 -0700 (PDT) Received: from [192.168.1.101] (bzq-84-111-131-91.red.bezeqint.net. [84.111.131.91]) by mx.google.com with ESMTPSA id nb8sm15860364wic.18.2014.05.19.09.32.48 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Mon, 19 May 2014 09:32:53 -0700 (PDT) Message-ID: <537A3227.9010506@gmail.com> Date: Mon, 19 May 2014 19:32:39 +0300 From: John English User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:24.0) Gecko/20100101 Thunderbird/24.5.0 MIME-Version: 1.0 To: Derby Discussion Subject: Re: Unique constraints and nulls References: <53737504.6000902@gmail.com> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Virus-Checked: Checked by ClamAV on apache.org On 19/05/2014 15:14, Knut Anders Hatlen wrote: > Hi John, > > I think CREATE UNIQUE INDEX ui ON Foo(A, B) might do what you want. In > contrast to a unique constraint, a unique index doesn't allow duplicate > nulls. OK, many thanks! -- John English