After upgrading to MySQL 5, one of my databases appeared empty even though the MyISAM tables existed in /var/lib/mysql/database-name. I found this error in the mysql log file in /var/log/mysqld.log:
090425 23:10:52 [ERROR] Invalid (old?) table or database name 'database-name'
Turns out that MySQL 5 doesn’t like database names that contain a hyphen. In the mysql directory, I see that it created a second directory for the database, but with the hyphen replaced with ‘@002d’.
drwx------ 2 mysql mysql 4096 Apr 25 23:10 database-name drwx------ 2 mysql mysql 4096 Apr 24 00:30 database@002dname
To resolve that I decided to replace the hyphen with an underscore. I stopped mysql, renamed /var/lib/mysql/database-name to /var/lib/mysql/database_name, and then ran this SQL to update the permissions:
UPDATE mysql.db SET Db = 'database_name' WHERE Db = 'database\-name'; FLUSH PRIVILEGES;
I could then see the tables using mysql from the command line. From there, I just updated the setting for the application to use the new name, and everything worked out find.