--- In firebird-support@yahoogroups.com, "skander_sp" <skander_sp@...>
wrote:

>
> > Don't do that. It doesn't work multi-user. Let me say that
> > again - assigning identifiers by finding the max identifier currently
> > used does not work in Firebird. You'll get duplicates.
>
> not really because every insertion is commited inmediatly.
> The value is generated in the before trigger.
> posibly duplicates in Therory? YES, Practically? NO.
>
> > Either use a generator or check the archives of this list of
> > multi-user safe ways of creating unique identifiers.
>
> Tks Ann, Tks Adam.
>
> In a perfect world will be the solution, but we don't live in.
>
> I can't use a generator for this work, because i need a REAL sucession
> without gaps.

You are not the only person who has encountered this problem. It is
often the result of legislation but of course it is going to mean that
at one time only one person can generate an invoice, and no other
invoice can safely be generated until the first is finalised.

I recommend you read the information behind "An Auditable Series of
Numbers" from http://www.ibobjects.com/TechInfo.html

Adam