Re: Does sequence take up stoarge in database?

In article <8iaru0$ugs$1_at_nnrp1.deja.com>,   Mark D Powell <markp7832_at_my-deja.com> wrote:
> In article <39477f35$0$504$7f31c96c_at_news01.syd.optusnet.com.au>,
> "junwen" <junwen_at_comic.com> wrote:
> > Hi,
> >
> > Can anybody tell me what is the use of sequence and does it take up
 any
> > storage in database
> > ?
> >
> > Regards,
> > Junwen
> >
> A sequence is Oracle's method of generating sequential numberic values
> usually used as keys. See the SQL manual entry for Create Sequence
 for
> syntax and options, and the Concepts manual for a description of their
> uses and limitations. Sequences are independent objects and do not
> belong to a specific table, but may be used by any user/process that
> has select privilege on the sequence.
>
> Sequences are dictionary entries that take a small amount of system
> tablespace to store and are made available for use via a shared pool
> buffer cache. At one time there was an comment about average storage
> space per sequence in the ver. 7 manuals, but I have long forgot what
> it was. The space required for a sequence is not significant.
> --
> Mark D. Powell -- The only advice that counts is the advice that
> you follow so follow your own advice --
>
Note, I forgot I switched from the Oracle boards to the theory board so my post should be modified to state that that this this is how Oracle implements its sequence generator and that several other rdbms such as DB2 implement sequence generators in a very similiar fashion.

Microsoft is in the minority by providing an autonumber class rather than a generator.

--
Mark D. Powell  -- The only advice that counts is the advice that
 you follow so follow your own advice --


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