How to test if a field has been entered in SQLForms30?

Hi

I have a number of fields which are optional on a form. When the form is comitted, I want to test which of these fields have been entered, and take different actions in a trigger depending on which ones were entered.

My questions are:

When you run a form, it is ready for the operator to enter a new record. Do all fields take on NULL as a start? In other words, what I'm getting at is to test if the fields are NULL/not NULL to determine if they were entered or not.

Is there any other way to determine if a field has obtained a value?

Massively appreciated.

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