Re: general theory behind 'primary_key' & 'auto_increment' flags, and ON DUPLICATE KEY UPDATE ?

On Jul 15, 2009, at 7:37 AM, Bastien Koert wrote:

On Wed, Jul 15, 2009 at 9:21 AM, Govinda<govinda.webdnatalk@gmail.com> wrote:

Reading docs.. I want to be sure of things... have your verification of my understanding(s)- Does setting a mysql db column (say "myPrimarykeyID") with the 'primary_key' & 'auto_increment' flags totally negate the logic for ever having to use ON DUPLICATE KEY UPDATE in an INSERT? Or is it that I can do an INSERT with SET myPrimarykeyID=someAlreadyExistingVal, a=1, b=2.... ON DUPLICATE KEY UPDATE a=edited1, b=edited2 ... I am trying to learn/work out the mysql/php code that will allow me to either create *or* edit a record, in one fell swoop. Thanks for any insight! -Govinda -- PHP Database Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php

If that is the goal use the REPLACE INTO sql syntax You really don't want to allow duplicates in primary keys, that completely negates the usefulness of that key

well isn't it that in order for the REPLACE INTO to replace the old row I have to try and replace a row with an already existing uniqueID? The same thing I would do to cause the INSERT.. SET .. ON DUPLICATE KEY UPDATE to kick in? Don't both methods equally effectively 'prevent duplicate primary keys from occurring'? -G