Re: advantages/disads of primary keys and indices?

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@acm.org> wrote in message news:785.574T2670T8255351mlemos@acm.org... > 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: http://phpclasses.UpperDesign.com/?user=mlemos@acm.org > -- > E-mail: mlemos@acm.org > URL: http://www.mlemos.e-na.net/ > PGP key: http://www.mlemos.e-na.net/ManuelLemos.pgp > -- > > > -- > PHP Database Mailing List (http://www.php.net/) > To unsubscribe, e-mail: php-db-unsubscribe@lists.php.net > For additional commands, e-mail: php-db-help@lists.php.net > To contact the list administrators, e-mail: php-list-admin@lists.php.net >