The trigger approach works like a charm. Thanks for the ideas...

pieter

_____

From: Helen Borrie [mailto:helebor@...]
Sent: 05 March 2004 09:41
To: firebird-support@yahoogroups.com
Subject: Re: [firebird-support] Questions about unique indexes


At 09:19 AM 5/03/2004 +0100, you wrote:

>Hi,
>
>imagine you have the following table:
>
>CREATE TABLE SUBSCRIPTION (
> SUBPK integer not null primary key,
> SUBURL varchar(1024) not null
>);
>
>I want to make the SUBURL a unique one, but since it's a varchar(1024),

this

>doesn't work as the column length is too long.
>
>Is there anything else I can do from the database side to ensure this field
>stays unique? Can I accomplish something with triggers?

create exception suburl_not_unique 'SubURL already exists';
commit;

create trigger bi_subscription for subscription
active before insert position 0
as
begin
...
if (exists (
select suburl from subscription
where suburl = new.suburl))
then
exception suburl_not_unique;
end





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