Received: from malur.postgresql.org ([217.196.149.56]) by arkaria.postgresql.org with esmtp (Exim 4.80) (envelope-from ) id 1VSBHR-0006hH-W8 for pgsql-sql@arkaria.postgresql.org; Fri, 04 Oct 2013 19:43:18 +0000 Received: from localhost ([127.0.0.1] helo=postgresql.org) by malur.postgresql.org with smtp (Exim 4.80) (envelope-from ) id 1VSBHR-0004v7-CG for pgsql-sql@arkaria.postgresql.org; Fri, 04 Oct 2013 19:43:17 +0000 Received: from magus.postgresql.org ([2a02:c0:301:0:ffff::29]) by malur.postgresql.org with esmtp (Exim 4.80) (envelope-from ) id 1VSBHP-0004tZ-LL for pgsql-sql@postgresql.org; Fri, 04 Oct 2013 19:43:15 +0000 Received: from mail-pd0-x22f.google.com ([2607:f8b0:400e:c02::22f]) by magus.postgresql.org with esmtp (Exim 4.80) (envelope-from ) id 1VSBHM-000612-Mk for pgsql-sql@postgresql.org; Fri, 04 Oct 2013 19:43:15 +0000 Received: by mail-pd0-f175.google.com with SMTP id q10so4382029pdj.20 for ; Fri, 04 Oct 2013 12:43:11 -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:cc:subject :references:in-reply-to:content-type:content-transfer-encoding; bh=TResrcgH9x9VQbS2rrEaVV8+B+FAduYl2KaZGFsGcFM=; b=a0VClwRDxIEDSFnGjlFZS31b0R6MvSnBzj6yEKmw/3DR7xAYiAQu+EGkHDL6GT3+jI /jAlxlGAlT19wrXrhuZIFxhmCslpvjaQ91vmdqKzqtJO8lxjpIu7kIpyhCoFQMcZe1hs /KmZ/vxUM6xJafqtgLTEAVWh827Ef3PtMq1GIwWXgJe0pb4UCJsL1ATdB2ydd+l5RfQo ilkV+YS6yjb4sYEca8CnClWi1rSLsl+mTh9d9+QLC28llsu8DDXWJo/OOoGpfP6mIF8L SIBiSILTlODD89sAeqxZ9Sy65azSBnN/efY4eZn4gQck0T/pp8hiTfJQEkWoUkIBolqy 472w== X-Received: by 10.68.197.104 with SMTP id it8mr16258367pbc.17.1380915790941; Fri, 04 Oct 2013 12:43:10 -0700 (PDT) Received: from killi.site ([199.48.193.199]) by mx.google.com with ESMTPSA id iu7sm16446904pbc.45.1969.12.31.16.00.00 (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Fri, 04 Oct 2013 12:43:09 -0700 (PDT) Message-ID: <524F1A4B.20606@gmail.com> Date: Fri, 04 Oct 2013 12:43:07 -0700 From: Adrian Klaver User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130801 Thunderbird/17.0.8 MIME-Version: 1.0 To: JORGE MALDONADO CC: "pgsql-sql@postgresql.org" Subject: Re: Unique index VS unique constraint References: In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Pg-Spam-Score: -2.0 (--) List-Archive: List-Help: List-ID: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: X-Mailing-List: pgsql-sql Precedence: bulk Sender: pgsql-sql-owner@postgresql.org On 10/04/2013 09:48 AM, JORGE MALDONADO wrote: > I have search for information about the difference between "unique > index" and "unique constraint" in PostgreSQL without getting to a > specific answer, so I kindly ask for an explanation that helps me > clarify such concept. The way I think of it is, that since the SQL standard does not mention indices an INDEX (UNIQUE or otherwise) is just the databases application of a constraint. So for practical purposes they are the same thing. > > Respectfully, > Jorge Maldonado -- Adrian Klaver adrian.klaver@gmail.com -- Sent via pgsql-sql mailing list (pgsql-sql@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-sql