Hello,
I need to check out if a description is already present in a table
while inserting or updating. I am wondering whether use an index on that
description or check it in the trigger after/begin insert/update.

Thanks for any advice

Marco

On Wed, 17 Oct 2007 09:38:42 +0200, Marco Cotroneo <m.cot@italia.it> wrote:

> Hello,
> I need to check out if a description is already present in a table
> while inserting or updating. I am wondering whether use an index on that
> description or check it in the trigger after/begin insert/update.

It depends on the cicumstances. Having a reasonably 'small' description
which should be enforced unique in a table would be best served with keys.
Longer blobs with text I wouldn't make a key of, and just check wether it
exists before a transaction.

A UNIQUE Key, and using an 'INSERT .... ON DUPLICATE KEY UPDATE ..' syntax
often does wonders.
--
Rik Wasmus

Rik Wasmus ha scritto:
> On Wed, 17 Oct 2007 09:38:42 +0200, Marco Cotroneo <m.cot@italia.it> wrote:
>
>> Hello,
>> I need to check out if a description is already present in a table
>> while inserting or updating. I am wondering whether use an index on
>> that description or check it in the trigger after/begin insert/update.
>
> It depends on the cicumstances. Having a reasonably 'small' description
> which should be enforced unique in a table would be best served with
> keys. Longer blobs with text I wouldn't make a key of, and just check
> wether it exists before a transaction.
>
> A UNIQUE Key, and using an 'INSERT .... ON DUPLICATE KEY UPDATE ..'
> syntax often does wonders.
Thanks for your replay. :-)