Hi Adriano,

> Sorry but i'm really a novice.

Having a look at the Firebird Generator Guide might help:

http://www.firebirdsql.org/manual/generatorguide.html
http://www.firebirdsql.org/pdfmanual/Firebird-Generator-Guide.pdf

That's two times the same guide, in HTML and PDF.

Especially the sections "SQL statements for generators" and "Using
generators to create unique row IDs" (with examples of BEFORE INSERT
triggers) may benefit you.

The first half of the guide tends to be a bit technical in places.
Don't worry if you don't understand all of the inner workings.


Greetings,
Paul Vinkenoog