Thanks Helen,

>Yes; and sometimes barcodes get duplicated (by the manufacturers, in

error) so a UNIQUE constraint can cause problems even where all items have a
barcode. Generally I would want to log such cases and flag the row for a
warning.>

Do you mean that you would just leave it there and flag it with some sort of
error code? Why?

Thanks in advance.

Best wishes,
jr

----- Original Message -----
From: "Helen Borrie" <helebor@...>
To: <ib-support@yahoogroups.com>
Sent: Friday, August 10, 2001 6:17 PM
Subject: Re: [ib-support] Unique key that accepts null


> At 06:09 PM 10-08-01 +0800, you wrote:
> >Thanks Helen,
> >
> >Would the trigger slows down performance noticeably? Since we are using
> >Exists here to test the whole table records' values.
>
> No, exists() is not very expensive, especially if you place an index on
the column that it check.
>
>
> >My purpose here is to allow users to key in barcode numbers for items
that
> >they keep, but some items are without barcode numbers, so I have to allow
> >null.
>
> Yes; and sometimes barcodes get duplicated (by the manufacturers, in
error) so a UNIQUE constraint can cause problems even where all items have a
barcode. Generally I would want to log such cases and flag the row for a
warning.
>
> Helen
>
> All for Open and Open for All
> InterBase Developer Initiative · http://www.interbase2000.org
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