> > In fact, the resulting variant is not null, instead is not
> > assigned! So I can't distinguish from a not found row and
> > a found row but with a null field:
>
> This is an attribute of all IBO columns as variants. The IBO code in
> IBA_Column.IMP does...
>
> function TIB_Column.GetAsVariant: Variant;
> begin
> Result := Unassigned;
> if not IsNull then
> ...

I chose to do it that way because there is a lot more flexibility when
moving values from one type to the next when you are dealing with unassigned
instead of null.

It was a case where I had to pick the lesser of two problems.

Jason Wharton
CPS - Mesa AZ
http://www.ibobjects.com