skander_sp wrote:

> I can't use a generator for this work, because i need a REAL sucession
> without gaps.

Then use one of the techniques for generating real successions without
gaps. They all have the effect of serializing inserts which may be
a problem, but there is no alternative. The simplest version is to
have a table consisting of a single record which contains the counter.
Update the counter and return the new value.

Low probability bugs will be a real nuisance to the person who takes
over your code. Be kind to future programmers.

Regards,

Ann