Re: Do Sequences Have Any Disadvantages?

Sequences are appropriate in a variety of situations. E.g., as a surrogate key when the natural key is concatenated; when you need a unique number (e.g., a PO system); I could come up with other examples, but I'm sure you can, too.

Oracle's sequences work very well. I have even been able to rig a system where distributed (non-replicated) tables share a sequence across servers! Not recommended, btw.

I am also a (light) Sybase DBA, and I would be curious as to what disadvantages you are referring to. If nothing else, I can confirm whether you have similar problems in Oracle.

From what you mention in your message, Oracle sequences seem appropriate.

Regards,
jh

Tom McCready <mccready_at_mail.loc.gov> wrote:

>I would like to hear when it is appropriate to use Sequences
>and when it is not. Are there disadvantages to Sequences which
>would force us to keep our own table of high keys, incremented
>by one each time a record is added?
>Many of our applications use a "one-up" number. The Sybase
>implementation has some disadvantages. How about the Oracle
>implementation? Thank you,
>Tom McCready, DBA, Library of Congress 202-707-5511
>--
>MZ
>
>

Jared Hecker, CODBA       | Oracle  and Sybase Architect and DBA
jared_at_planet.net          | - consulting in the 
76276.740_at_compuserve.com  |   NYC/NJ region