SQL*Forms PRE-QUERY trigger question...

Using Forms version 3.

I have a form with both database and non-database fields on it. I want to be able to query the db from the non-database fields. In section 3-28 of my Forms 3.0 manual it tell me that I can populate something called an Example Record with a pre-query trigger.

So what I want to do is extract a value from the database based on the contents of one of the non-database fields, populate a database field in the Example Record, and then execute the query.

How do I do it?

Thanks in advance, Michael.

-- 
Michael Collier (Programmer)                 The Computer Unit,
Email: M.P.Collier_at_uk.ac.city                The City University,
Tel: 071 477-8000 x3769                      London,
Fax: 071 477-8565                            EC1V 0HB.