zend Auth add more credential

   // Get our authentication adapter and check credentials
        $adapter = $this->_getAuthAdapter();
   
    //Need to add more credential for user
    $select = $adapter->getDbSelect();
        $select->where('status = 1 AND password is not null AND password!=""');
 $adapter->setIdentity($values['username']);
        $adapter->setCredential(md5($values['password']));

        $auth = Zend_Auth::getInstance();
        $result = $auth->authenticate($adapter);
        if ($result->isValid()) {
            $user = $adapter->getResultRowObject();
            $auth->getStorage()->write($user);
            return $this->_redirect('/sitemgr/pages');
        }



//or else we can use following simple code

$authAdapter->setTableName('register')
            ->setIdentityColumn('username')
            ->setCredentialColumn('pwd')
            ->setCredentialTreatment('? AND status = "active"');