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php-db | 2001062

Re: [PHP-DB] advantages/disads of primary keys and indices? From: Noah Spitzer-Williams (noahsw <email protected>)
Date: 06/23/01

Yeah the keys would be part of the first condition of the where clause...

this table is like this:
username | siteid | bannerid | clicks | someotherstat

an update would be like: update tbl set clicks=clicks+1 where
username='something' and siteid='something' and bannerid='something'

a select would be: select clicks from tbl where username='something' and
siteid='something' and bannerid='something'

so knowing this, does it make sense to make primary keys out of
username,siteid,bannerid?

Thanks!

- Noah

""Manuel Lemos"" <mlemos <email protected>> wrote in message
news:785.574T2670T8255351mlemos <email protected>
> Hello Noah,
>
> On 23-Jun-01 12:10:20, you wrote:
>
> >I see,
>
> >What about if you had 3 or 4 columns that would always be unique, is
there
> >an advantage to naming them as primary keys? does this slow inserts
because
> >it has to check if theres a duplicate entry?
>
> What really slows down is updating the index with the new entry value.
>
> Anyway, some times it may pay to slow down inserts and updates for very
> large tables. You have to check if the indexes/primary keys that you are
> adding are used as the first condition of the WHERE clause.
>
>
>
> Regards,
> Manuel Lemos
>
> Web Programming Components using PHP Classes.
> Look at: email protected>?subject=Re:%20[PHP-DB]%20advantages/disads%20of%20primary%20keys%20and%20indices?&replyto=9h2jmm$ej3$1 <email protected>">mlemos <email protected>">http://phpclasses.UpperDesign.com/?user=mlemos <email protected>
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