Subject Re: [IBO] Problem with TIB_LOOKUPCOMBO
Author TeamIBO
> I discovered what was causing the problem, I just can't understand
> why it would happen. Problem was that somehow (through poor error
> checking on my part I suspect) I allowed a blank city name to be
> stored in the file. For whatever reason, this caused the lookup to
> function incorrectly. As soon as I deleted the blank city, all
> worked fine.

By "blank" you mean NULL ?

Nulls in a lookup list cause all sorts of problems. IB sorts NULL to
the end of a list (whether you sort ASC or DESC). The client sees
nulls as blank strings which short sort to the top.

The reason why the behaviour of lookupcombo appears strange is the
algorithm attempts to optimise the search by jumping forward through
the list and then scrolling forward or backward according to the new
position. So the search jumps forwards - hits the null at the end and
tries to scroll forward (because everyone except SQL knows that blanks
sort to the top ;-) Since it does not find a matching result the
search fails.

And now that you mention it, I do remember hearing this problem
reported before and should have thought to mention it as a
possibility. Cant remember everything :-)

Geoff Worboys - TeamIBO
Telesis Computing