Re: Add a serial column to a table based on a sort clause

From: David Fetter <david(at)fetter(dot)org>
To: Igor Katson <descentspb(at)gmail(dot)com>
Cc: pgsql-general(at)postgresql(dot)org
Subject: Re: Add a serial column to a table based on a sort clause
Date: 2009-09-03 01:11:19
Message-ID: 20090903011119.GN8410@fetter.org
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On Wed, Sep 02, 2009 at 04:40:13PM +0400, Igor Katson wrote:
> I have a table, which has a creation_ts (timestamp) column, but does
> not have a id (serial) column. I want to add such a one, but, AFAIK,
> if I enter
>
> ALTER TABLE table ADD COLUMN id serial
>
> it will randomly put the sequence numbers.

"Random" is how you should think of them. Sequences guarantee only
uniqueness. Neither order nor gap-less numbers, nor any other
property apply to them.

Cheers,
David.
--
David Fetter <david(at)fetter(dot)org> http://fetter.org/
Phone: +1 415 235 3778 AIM: dfetter666 Yahoo!: dfetter
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