auto-increment

Here is a table in MySQL 5.3.X+ db: CREATE TABLE members` ( `id` int(11) UNSIGNED NOT NULL AUTO_INCREMENT, `memberid` VARCHAR( 30 ) NOT NULL , `Time` TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP , `firstname` VARCHAR( 50 ) NULL , `lastname` VARCHAR( 50 ) NULL , UNIQUE (memberid), PRIMARY KEY (id) ) ENGINE = MYISAM; Id column is never used in queries, it is just for visual convenience (so it's easy to see how the table grows). Memberid is an actual key, is unique, and memberid is used in queries to identify any member (WHERE memberid='abcde'). My question is: how to keep auto_increment, but

I have a pre-existing table, containing 'fname', 'lname', 'email', 'password' and 'ip'. But now I want an auto-increment column. However, when I enter: ALTER TABLE users ADD id int NOT NULL AUTO_INCREMENT I get the following: #1075 - Incorrect table definition; there can be only one auto column and it must be defined as a key Any advice?:) Muhammad Asif Mahmood Try this ALTER TABLE `users` ADD `id` INT NOT NULL AUTO_INCREMENT PRIMARY KEY If you don't care whether the auto-id is used as PRIMARY KEY , you can just do ALTER TABLE `myTable` ADD COLUMN `id` INT AUTO_INCREMENT UNIQUE FIRST; I just

What are the other ways of achieving auto-increment in oracle other than use of triggers? As far as I can recall from my Oracle days, you can't achieve Auto Increment columns without using TRIGGER. Any solutions out there to make auto increment column involves TRIGGER and SEQUENCE (I'm assuming you already know this, hence the no trigger remarks). You can create and use oracle sequences. The syntax and details are at http://www.techonthenet.com/oracle/sequences.php Also read the article http://rnyb2.blogspot.com/2006/02/potential-pitfall-with-oracle-sequence.html to understand the limitations