> If I leave, for example, the field Description = NULL (it has no
> default value) with CheckRequired := False, I get no error and the
> NULL field is successfully posted to the database. Instead, if
> CheckRequired := True, I get an IBO error message. In either case the
> OnError handler of TIB_Query is *never* fired.

So - is the error you are getting there from the connection
onError rather than the query?

> I forgot to mention that I'm using Firebird 1.0.2.908

That should not be a problem, but I am still on the
'special' 1.0.0 using an older version of IBO4 so there may
be differences.

>>just adding the NOT NULL in the query is not the
>>correct way of doing it
>
> But I have *not* added the NOT NULL in the query. I have said that the
> REQUIRED check boxes for *all* fields in the TIB_Query are grayed, so
> I suppose that IBO should by-pass this test and let the database
> return an error in this case.

I am seeing an error on my NOT NULL colums, so next question
- IS the post actually putting NULL values into the record?
Or are we seeing an example of IBO4 providing a value rather
than NULL and trying to be helpfull <g>

One of the things I try when I get these sorts of problem is
to try doing an insert in IB_SQL just to test my logic -
silly things like triggers that do the wrong thing - etc.
This should show the correct responce, but since it is also
an IBO4 application, then it might provide some help.

--
Lester Caine
-----------------------------
L.S.Caine Electronic Services