Botsko.net - Web Development in Portland, Oregon » MySQL http://www.botsko.net/blog continuing education Thu, 15 Dec 2011 20:07:58 +0000 en hourly 1 http://wordpress.org/?v=3.3.1 Tech-Tidbit: Altering Primary Keys in MySQL http://www.botsko.net/blog/2007/03/29/tech-tidbit-altering-primary-keys-in-mysql/ http://www.botsko.net/blog/2007/03/29/tech-tidbit-altering-primary-keys-in-mysql/#comments Thu, 29 Mar 2007 16:04:49 +0000 Michael Botsko http://www.botsko.net/blog/?p=181 I’ve come to design every database table with an auto-increment id field that is a primary key. However, sometimes I work on projects where tables have no such column and may have duplicate rows. In order to drop the existing primary key definitions I run:

[mysql]
ALTER TABLE mytable DROP PRIMARY KEY;
[/mysql]

Then, I add a new one:

[mysql]
ALTER TABLE `mytable` ADD `id` INT NOT NULL AUTO_INCREMENT PRIMARY KEY FIRST ;
[/mysql]

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