If your DB contains only MyISAM tables (do not use this method if you have InnoDB tables):
- shut down the MySQL server
- go to the mysql
data directory and rename the database directory (Note: non-alpha characters need to be encoded in a special way)
- restart the server
- adjust privileges if needed (grant access to the new DB name)
You can script it all in one command so that downtime is just a second or two.
