无法加载数据库驱动 Think\Db\Driver

return array(
//'配置项'=>'配置值'
'TMPL_PARSE_STRING'=>array(
'ADMIN'=>ROOT.'/Application/Public/Admin',

),
'DB_TYPE'=>'mysql',
'DB_HOST'=>'localhost',
'DB_NAME'=>'db_oa',
'DB_USER'=>'root',
'DB_PWD'=>'123456',
'DB_PORT'=>'3306',
'DB_PREFIX'=>'sp_'
);