//** UsuariosDAO.php extends DAO.php **//
public function queryChkLogin(\Projeto\Core\Model\Usuarios $usuario)
{
    try
    {
        $dql = "SELECT u
                FROM \Projeto\Core\Model\Usuarios u
                WHERE u.login = :login AND
                      u.id <> :id";

    $usuarioLogin = "'" . $usuario->getLogin() . "'";
        $params       = array('login' => $usuarioLogin,
                        'id'    => $usuario->getId());

        return $this->queryDAO($dql);
    } catch (Exception $e)
    {
        return false;
    }
}