global.php
////////////////
return array(
    'db' => array(
        'driver' => 'Pdo',
        'driver_options' => array(
            PDO::MYSQL_ATTR_INIT_COMMAND => 'SET NAMES \'UTF8\''
        ),
    ),
    'service_manager' => array(
        'factories' => array(
            'Zend\Db\Adapter\Adapter'
                    => 'Zend\Db\Adapter\AdapterServiceFactory',
        ),
    ),

);
//////////////////
local.php
return array(
    'db' => array(
        'dsn'      => 'mysql:dbname=SSN;host=localhost',
        'username' => 'root',
        'password' => 'toor',
    ),
);

/////
controller
<?php
namespace Student\Controller;

use Zend\Mvc\Controller\AbstractActionController;
use Zend\View\Model\ViewModel;
use Student\Form\LoginInput;
use Student\Form\LoginValidate;
use Zend\Authentication\Adapter\DbTable as AuthAdapter;



class StudentController extends AbstractActionController{
    private $adapter;

    function indexAction() {
        $view = new ViewModel();
        return $view;
    }

    function loginAction(){
        $form = new LoginInput();
        $validator = new LoginValidate();
        $request = $this->getRequest();
        if($request->isPost()){

            $form->setData($request->getPost());
            $form->setInputFilter($validator);
            if($form->isValid()){
                $Postdata = $request->getPost();

                $authAdapter = new AuthAdapter($this->getAdapter(),
                               'students',
                               'email',
                               'password'
                               );
                //set user password
                $authAdapter
                ->setIdentity($form->getValue('email'))
                ->setCredential($form->getValue('password'));


                //echo the result
                var_dump($authAdapter->authenticate());

                // Print the result row



            }
        }
        $view = new ViewModel(array('form'=>$form));
        return $view;
    }

    function registerAction(){
        $view = new ViewModel();
        return $view;
    }

    public function getAdapter()
    {
    if (!$this->adapter) {
      $sm = $this->getServiceLocator();
      $this->adapter = $sm->get('Zend\Db\Adapter\Adapter');
    }
    return $this->adapter;
    }
}