it's not an innodb thing: http://dev.mysql.com/doc/refman/5.0/en/create-table.html
"Note "There can be only one AUTO_INCREMENT column per table, it must be indexed, and it cannot have a DEFAULT value. An AUTO_INCREMENT column works properly only if it contains only positive values. Inserting a negative number is regarded as inserting a very large positive number. This is done to avoid precision problems when numbers “wrap” over from positive to negative and also to ensure that you do not accidentally get an AUTO_INCREMENT column that contains 0." -----Original Message----- From: "Yang Zhang" <yanghates...@gmail.com> Sent: Monday, January 25, 2010 10:21am To: mysql@lists.mysql.com Subject: auto_increment without primary key in innodb? In innodb, is it possible to have an auto_increment field without making it a (part of a) primary key? Why is this a requirement? I'm getting the following error. Thanks in advance. ERROR 1075 (42000): Incorrect table definition; there can be only one auto column and it must be defined as a key -- Yang Zhang http://www.mit.edu/~y_z/ -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/mysql?unsub=...@thefsb.org -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/mysql?unsub=arch...@jab.org