MySQL Reference Manual :: 13.1.1 ALTER DATABASE Syntax

       ALTER {DATABASE | SCHEMA} [db_name]
       alter_specification [, alter_specification] ...
       
       alter_specification:
       [DEFAULT] CHARACTER SET charset_name
       | [DEFAULT] COLLATE collation_name
     

ALTER DATABASE allows you to change the overall characteristics of a database. These characteristics are stored in the db.opt file in the database directory. To use ALTER DATABASE, you need the ALTER privilege on the database.

The CHARACTER SET clause changes the default database character set. The COLLATE clause changes the default database collation. Character set and collation names are discussed in Chapter 10, Character Set Support.

ALTER DATABASE was added in MySQL 4.1.1. Beginning with MySQL 4.1.8, the database name can be omitted. The statement applies to the default database in this case. ALTER SCHEMA can be used as of MySQL 5.0.2.