12.1.32. RENAME DATABASE Syntax
RENAME {DATABASE | SCHEMA} db_name TO new_db_name;
This statement was added in MySQL 5.1.7 but was found to be dangerous and was removed in MySQL 5.1.23. It was intended to enable upgrading pre-5.1 databases to use the encoding implemented in 5.1 for mapping database names to database directory names (see Section 8.2.3, “Mapping of Identifiers to File Names”). However, use of this statement could result in loss of database contents, which is why it was removed. Do not use RENAME DATABASE in earlier versions in which it is present.
To perform the task of upgrading database names with the new encoding, use ALTER DATABASE db_name UPGRADE DATA DIRECTORY NAME instead (see Section 12.1.1, “ALTER DATABASE
Reference: http://dev.mysql.com/doc/refman/5.1/en/rename-database.html