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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

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?

""Manuel Lemos"" <mlemos <email protected>> wrote in message
news:618.573T978T13634015mlemos <email protected>
> Hello Noah,
>
> On 22-Jun-01 21:17:35, you wrote:
>
> >what are the advantages and disadvantages of primary keys and indices?
>
> A primary key is a unique index.
>
> Use indexes for the fields that will be most looked up in the first
> condition of the WHERE clause of your SQL queries, especially if your
> tables will hold many values, but beware that indexes also take disk
space.
>
>
> 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=9h2bgr$jm3$1 <email protected>">mlemos <email protected>">http://phpclasses.UpperDesign.com/?user=mlemos <email protected>
> --
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> URL: http://www.mlemos.e-na.net/
> PGP key: http://www.mlemos.e-na.net/ManuelLemos.pgp
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