--创建数据库
create {database | schema} [if not exists] db_name
    [
        create_specification 
        [, create_specification] ...
    ]
create_specification:
    [default] character set charset_name--指定数据库字符集（Charset），
    |[default] collate collation_name--指定字符集的校对规则，collation_name为校对规则名称
--修改数据库
alter {database | schema} [db_name]
    alter_specification [, alter_specification] ...
alter_specification:
--删除数据库
drop database  [if exists] db_name