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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Thread: | |
Lists: | pgsql-general |
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/
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