public static function update($collection, $criteriaQuery, $data, $multiple = false)
  {
    static::checkConnexion();
    $collection = self::$db->$collection;
    if (is_string($criteriaQuery)) {
      $criteriaQuery = json_decode($criteriaQuery, true);
      if (!$criteriaQuery) {
        throw new \Exception('criteriaQuery JSON formulée incorrectement');
      }
    }
    if (is_string($data)) {
      $data = json_decode($data, true);
      if (!$data) {
        throw new \Exception('data JSON formulé incorrectement');
      }
    }
    $r = $collection->update($criteriaQuery, $data, array('multiple' => $multiple, 'upsert' => false));
    if ($r['updatedExisting'] && $r['ok']) {
      return true;
    }
    return false;
  }