gift function

  public function setGift()
  {
    $db = Environment::getDatabase();
    $error = "Je hebt vandaag al je cadeau gekregen!";


    if(isset($_POST['submit_gift']))
    {
      $query = $db->query("SELECT * FROM gifts WHERE user_id = '". intval($this->_id) . "'AND date = '" . date("d-m-Y") . "' LIMIT 1");

      if(mysqli_num_rows($query) != 0)
      {
        return $error;
      } else {

        Util::Gift();

        $db->query("INSERT INTO gifts (user_id,date) VALUES ('". intval($this->_id)"', '" . date("d-m-Y") ."' )");
        $db->query("UPDATE users SET $gift = $gift + $value WHERE id = '". intval($this->_id)"' LIMIT 1") or die(Environment::getDatabase()->error);
      }

    }