General Error handling

Question

I've managed to get myself confused with error handling in Forms 6i.
If I have a trigger that does a 'commit-form' like this
commit_form;
IF NOT form_success THEN
RAISE form_trigger_failure;
END IF;
EXCEPTION
WHEN OTHERS THEN;
END;
and the commit_form fails due to a mandatory field being missing (or similar) then what happens first?
Does my ON-ERROR trigger fire?
Does the form_success check fail and raise form_trigger failure?
Does my exception block get used?
Or does more than 1 happen??
I could - of course - find the answer to this through debug but I'm looking for a more generic answer if possible.
Thanks - Sean.

Answer 1

What happens first?  The forms validation process runs and informs user that the field is required.
Does On-Error fire?  Yes, if you have one in your form.
Does the form_success check fail and raise form_trigger failure?  Yes -- but ONLY if your On-error raises Form_trigger_failure.  If it does not, you have lots of problems.
Does my exception block get used?  Yes.  Raising Form_trigger_failure causes control to pass to the exception handler.  But I never use an exception handler except when I code SQL commands.
Now...  After commit_form, you should also check Form_Status.  Read the help topic on the Form_Success built-in.
My standard C00_Commit program unit does this:
  COMMIT_FORM;
  IF :SYSTEM.FORM_STATUS <> 'QUERY'
  OR NOT FORM_SUCCESS THEN
    RAISE FORM_TRIGGER_FAILURE;
  END IF;
END;