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

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От David Fetter
Тема Re: Add a serial column to a table based on a sort clause
Дата
Msg-id 20090903011119.GN8410@fetter.org
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Ответ на Add a serial column to a table based on a sort clause  (Igor Katson <descentspb@gmail.com>)
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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@fetter.org> http://fetter.org/
Phone: +1 415 235 3778  AIM: dfetter666  Yahoo!: dfetter
Skype: davidfetter      XMPP: david.fetter@gmail.com

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