How to work correctly in a net with several inserts?

I am needing help in catching the values of a TRIGGER or of a
GENERATOR using IBO.

Actually I am developing a system of sales and I need with urgency
to know as to catch a GENERATOR without there is duplication of data
among the users.

I have the following fields:

Table of Sales
== == == == == == ==
CODESALE
...

Table of requested products
== == == == == == == == == == ==
CODE PRODUCT
CODESALE

Did I already create a generator for CODESALE even so me precise to
catch this value in advance because in a net as I can guarantee that
other station doesn't catch the same code that of another stations?
When catching this value me precise to throw it in the table DETAIL
in the field CODESALE. Would a functional example be possible of
that? Using IBX I got to find a component that the number of
GENERATOR came back. How to do that with IBO?
Thank you

Juarez