"Rajesh" <r@h.c> wrote in message
news:Cn3Qa.11323$Kw1.2567@nwrdny02.gnilink.net...
> Can some one explain the Pros and Cons of using Identity columns?
>
> -Rp©
>


Pro: they're a very fast way of generating sequential numbers (since
no disk I/O or transactional locking is needed for generating a new
value.

Cons: in pre-12.0: there's a risk of "identity gaps", see
www.sypron.nl/idgaps.html for details.
In 12.0+: identity gaps can be limited or avoided with the
'identity_gap' setting -- when you use this, there are few
disadvantages left (but those are solved in 12.5.0.3 and 12.5.1).

HTH,

Rob
-------------------------------------------------------------
Rob Verschoor

Certified Sybase Professional DBA for ASE 12.5/12.0/11.5/11.0
and Replication Server 12.5

New book(coming soon): 'Tips, Tricks & Recipes for Sybase ASE'
For details, see http://www.sypron.nl/ttr

mailto:rob@DO.NOT.SPAM.sypron.nl.REMOVE.THIS.DECOY
http://www.sypron.nl
Sypron B.V., P.O.Box 10695, 2501HR Den Haag, The Netherlands
-------------------------------------------------------------

Rob Verschoor wrote:

> In 12.0+: identity gaps can be limited or avoided with the
> 'identity_gap' setting -- when you use this, there are few
> disadvantages left (but those are solved in 12.5.0.3 and 12.5.1).

What disadvantages have been solved in 12.5.x?

-am © 2003

"Anthony Mandic" <k9@hotmail.com> wrote in message
news:3F129D87.5DB46ADC@hotmail.com...
> Rob Verschoor wrote:
>
> > In 12.0+: identity gaps can be limited or avoided with the
> > 'identity_gap' setting -- when you use this, there are few
> > disadvantages left (but those are solved in 12.5.0.3 and 12.5.1).
>
> What disadvantages have been solved in 12.5.x?
>
> -am © 2003

In 12.5.0.3, some identty-related built-ins were added as well as the
command 'set identity_update'.
In the beta version of 12.5.1, it is possible to reset the identity
counter to an arbitrary value with sp_chgattribute.

Rob
-------------------------------------------------------------
Rob Verschoor

Certified Sybase Professional DBA for ASE 12.5/12.0/11.5/11.0
and Replication Server 12.5

New book(coming soon): 'Tips, Tricks & Recipes for Sybase ASE'
For details, see http://www.sypron.nl/ttr

mailto:rob@DO.NOT.SPAM.sypron.nl.REMOVE.THIS.DECOY
http://www.sypron.nl
Sypron B.V., P.O.Box 10695, 2501HR Den Haag, The Netherlands
-------------------------------------------------------------

Rob Verschoor wrote:

> In 12.5.0.3, some identty-related built-ins were added as well as the
> command 'set identity_update'.
> In the beta version of 12.5.1, it is possible to reset the identity
> counter to an arbitrary value with sp_chgattribute.

Very interesting ...

-am © 2003