Re: Question on select count()

jpbelang_at_hotmail.com (JP Belanger) wrote in message news:<b399d6ce.0408170627.12849129_at_posting.google.com>...
> afilonov_at_yahoo.com (Alex Filonov) wrote in message news:<336da121.0408161150.2c0d78d9_at_posting.google.com>...
> >
> >
> > If you are trying to restrict number of rows to <= 50, there is something
> > wrong with database design. It'll help if you post what you are trying
> > to achieve (in simple words)...
>
> Are you saying I was unclear ? :)
>
> I keep track of sessions in a database. Exceeding a fixed number of
> sessions should not be allowed.
>

You mean, each session is registering itself in some table? Maybe you can use v$session virtual table?
Another way is to create a table with fixed number of rows. Would create a lot of headache: you need to update a row when session is registering itself and update again when it's de-registering (and you need a monitor which would detect dead session and de-register them). Another problem with this design is that session needs to connect to database to try to register itself...

> The reason I do not keep the cound in the Java application was that I
> wanted to keep the application stateless, to allow for simple load
> balancing. I thought the database could help me, but at the same
> time, I think helping me, the database would sacrifice a lot of
> performance.

Maybe not. Depends on what kind of operations do you do against the database.
BTW, do you really need to restrict the number of sessions? And, is it possible to use restrictions built-in into Oracle, like restrictions on number of sessions, processes or transactions? Received on Tue Aug 17 2004 - 23:22:24 CEST