codeigniter使用pdo的参考配置

$db['default'] = array(
   'dsn'  => 'mysql:host=127.0.0.1;port=3306;dbname=test',//关键是这个得配置
   'hostname' => '',
   'username' => 'username',
   'password' => 'password',
   'database' => 'test',
   'dbdriver' => 'pdo',
   'dbprefix' => '',
   'pconnect' => FALSE,
   'db_debug' => TRUE,
   'cache_on' => TRUE,
   'cachedir' => '',
   'char_set' => 'utf8',
   'dbcollat' => 'utf8_general_ci',
   'swap_pre' => '',
   'encrypt' => FALSE,
   'compress' => TRUE,
   'stricton' => FALSE,
   'failover' => array(),
   'save_queries' => TRUE
);