Re: Need help requiring uniqueness in text columns

From: Matthew Wilson <matt(at)tplus1(dot)com>
To: pgsql-general(at)postgresql(dot)org
Subject: Re: Need help requiring uniqueness in text columns
Date: 2008-01-02 15:11:09
Message-ID: slrnfnnacd.dk.matt@coleridge.tplus1.com
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-general

On Wed 02 Jan 2008 04:23:46 AM EST, Pavel Stehule wrote:
> Hello
>
> IDEA 3:
>
> Use two hash functions:
>
> CREATE UNIQUE INDEX uidx ON TEST((decode(md5(a),'hex')),(hashtext(a)));
>
> removing spaces helps
> CREATE UNIQUE INDEX uidx ON test((decode(md5(lower(replace(a,' ',''))),'hex')));
>
> Regards
> Pavel Stehule
>
> CREATE UNIQUE INDEX nodups on MESSAGE (my_timestamp_col, md5(my_text_col));

What is the advantage of this method?

--
Programming, economics, gardening, life in Cleveland.
http://blog.tplus1.com

In response to

Responses

Browse pgsql-general by date

  From Date Subject
Next Message Pavel Stehule 2008-01-02 15:23:08 Re: Need help requiring uniqueness in text columns
Previous Message William Temperley 2008-01-02 14:17:42 Creating XML/KML documents from single tables