From: Andreas Kretschmer <akretschmer@spamfence.net>
To: pgsql-sql@postgresql.org
Subject: Re: Prevent double entries ... no simple unique index
Date: Thu, 12 Jul 2012 07:14:45 +0200
Message-ID: <20120712051445.GA5421@tux> (raw)
In-Reply-To: <C4DAC901169B624F933534A26ED7DF310861B61A@JENMAIL01.ad.intershop.net>
References: <4FFD3050.3010509@gmx.net>
<20120711081607.GA17798@tux>
<20120711082458.GA19013@tux>
<C4DAC901169B624F933534A26ED7DF310861B61A@JENMAIL01.ad.intershop.net>
Marc Mamin <M.Mamin@intershop.de> wrote:
> >
> > Or this one:
> >
> > test=*# create unique index on log((case when state = 0 then 0 when
> > state = 1 then 1 else null end));
> > CREATE INDEX
> >
> >
> > Now you can insert one '0' and one '1' - value - but no more.
>
> Hi,
>
> A partial index would do the same, but requires less space:
>
> create unique index on log(state) WHERE state IN (0,1);
Right! ;-)
Andreas
--
Really, I'm not out to destroy Microsoft. That will just be a completely
unintentional side effect. (Linus Torvalds)
"If I was god, I would recompile penguin with --enable-fly." (unknown)
Kaufbach, Saxony, Germany, Europe. N 51.05082°, E 13.56889°
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: akretschmer@spamfence.net
Subject: Re: Prevent double entries ... no simple unique index
In-Reply-To: <20120712051445.GA5421@tux>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox