> I have an InnoDB table similar to this: > > CREATE TABLE Target > (IMSI VARCHAR(15) ASCII, > IMEI VARCHAR(15) ASCII, > UNIQUE KEY (IMSI, IMEI)); > > After playing a bit with it, I managed to add duplicate records, if one of > the fields was a NULL: > > +-----------------+-----------------+ > | IMSI | IMEI | > +-----------------+-----------------+ > | NULL | 35195600126418 | > | NULL | 35195600126418 | > +-----------------+-----------------+ > > > Is this a bug, or a feature? :-)
A feature. NULL isn't equal to NULL. > If it is a feature, than how can I assure uniqueness for a table in a sense > that won't allow such duplicates? If you don't want to have NULL, use a "primary key" instead of a "unique key". Martijn Tonies Database Workbench - development tool for MySQL, and more! Upscene Productions http://www.upscene.com My thoughts: http://blog.upscene.com/martijn/ Database development questions? Check the forum! http://www.databasedevelopmentforum.com -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED]
