public static function getInstance()
 {
     if (!self::$_instance) {
         // Si aucun instance, creer l'instance
         self::$_instance = new self();
     }
     return self::$_instance;
 }
 function __construct()
 {
     $dbsingleton = monSQL::getInstance();
     $this->_db = $dbsingleton->getConnection();
 }