/**
  * Recupere une instance de DB
  * @return object $instance
  */
 public function getInstance()
 {
     global $_SQL;
     if (!isset(self::$instance)) {
         self::$instance = new Db_buckutt('mysql');
         self::$instance->connect($_SQL['host'], $_SQL['base'], $_SQL['user'], $_SQL['pass']);
     }
     return self::$instance;
 }