agora inbox for pgsql-sql@postgresql.org  

help / color / mirror / Atom feed

From: Adrian Klaver <adrian.klaver@gmail.com>
To: JORGE MALDONADO <jorgemal1960@gmail.com>
Cc: pgsql-sql@postgresql.org <pgsql-sql@postgresql.org>
Subject: Re: Unique index VS unique constraint
Date: Fri, 04 Oct 2013 12:43:07 -0700
Message-ID: <524F1A4B.20606@gmail.com> (raw)
In-Reply-To: <CAAY=A78oJ--0aPm4E6ASJ32Z3UHk0nOqHQ_SvrtjOmq7i=UKDQ@mail.gmail.com>
References: <CAAY=A78oJ--0aPm4E6ASJ32Z3UHk0nOqHQ_SvrtjOmq7i=UKDQ@mail.gmail.com>
List-Unsubscribe: <mailto:majordomo@postgresql.org?body=unsub%20pgsql-sql>

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

view thread (9+ messages)  latest in thread

Message-ID: <524F1A4B.20606@gmail.com>
Permalink:  ../524F1A4B.20606@gmail.com/
Also on:    postgresql.org/message-id/524F1A4B.20606@gmail.com

reply

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Reply to all the recipients using the --to and --cc options:
  reply via email

  To: pgsql-sql@postgresql.org
  Cc: adrian.klaver@gmail.com, jorgemal1960@gmail.com
  Subject: Re: Unique index VS unique constraint
  In-Reply-To: <524F1A4B.20606@gmail.com>

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

This inbox is served by agora; see mirroring instructions
for how to clone and mirror all data and code used for this inbox