Rohit,

> Besides the problme is the null.

Then the problem is either in the design of the database, or in the
client applications, or both.

> Using a statement such as (xx > 0) fails to find them and so does (xx<=
> 0).... it is illogical.

So is null greater than, equal to or less than zero?

> Unfortunately the defaults in Interbase do not work when using IBO.

There are many ways to "make them work", but this is stuff for another
list.

> IBO should save '' and 0 for nulls in strings and integers.

I think there are settings to do it at many different levels.
Ciao
--
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_/\/ando