Right, I saw the docs. I'm fine with creating an index on it, but the only way I've successfully created a table with auto_increment is by making it a primary key. And I still don't understand why this requirement is there in the first place.
On Mon, Jan 25, 2010 at 10:32 AM, Tom Worster <f...@thefsb.org> wrote: > 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 > > > > -- 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=arch...@jab.org
