Thanks to all of you for replying and throwing light on this issue.

Well as Helen has shown a example of table which has strings stored
in the form of varchar. So if have a string "abc" already in the
database which has unique constraint and indexed and i try to
insert "abc " well it pass through the equating stage but it will
fail in the inserting stage.

I will think of the options mentioned here.

Thanks once again.
Cheers!

--- In firebird-support@yahoogroups.com, Svein Erling Tysvær
<svein.erling.tysvaer@...> wrote:

>
> I cannot comment on Helen's and Martijns e-mails, I've never tried

to

> get into this kind of trouble. Though I may comment on one thing.
>
> > If I use LIKE then it works fine but the trade off will be i

don't

> > have to use indexing then which will be big loss i suppose.
>
> If the statement
>
> A = B
>
> returns too many rows, whereas
>
> A LIKE B
>
> returns the rows you want, but without using any index, then why

don't

> you simply do
>
> (A = B) AND (A LIKE B)
>
> to get the answer you want while using an index?
>
> Set
>