Create review like module in magento

I have created a module by which we can marked product review helpful or not

Create a table

CREATE TABLE IF NOT EXISTS `review_like` (

  `id` int(11) NOT NULL AUTO_INCREMENT,

  `product_id` int(11) NOT NULL,

  `review_id` int(11) NOT NULL,

  `customer_id` int(11) NOT NULL,

  `like` int(11) NOT NULL,

  `notlike` int(11) NOT NULL,

  PRIMARY KEY (`id`),

  UNIQUE KEY `product_id` (`product_id`,`review_id`,`customer_id`)

)

Modify review_detail  add two field like, notlike

Add the below code in the app\code\core\Mage\Review\etc\config.xml

<review_like>
    <table>review_like</table>
 </review_like>

Add the following code in your review page after the review description

app\design\frontend\base\default\template\review\product\view\list.phtml

<?php

      $like_url = $this->getUrl('review/product/list').'id/'.$_review->getEntityPkValue().'/rev/'.$_review->getReviewId().'/lik/';                                                                     

 ?>

               <p class="rev_h"> Was this review helpful?

               <?php if(!Mage::getSingleton('customer/session')->isLoggedIn()):?> <a href="<?php echo $this->getSkinUrl(''); ?>customer/account/login/"><?php else: ?>             

               <a href="<?php echo $like_url; ?>1"><?php endif?>Yes</a>(<?php echo $this->htmlEscape($_review->getLike()) ?>) /

               <?php if(!Mage::getSingleton('customer/session')->isLoggedIn()):?> <a href="<?php echo $this->getSkinUrl(''); ?>customer/account/login/"><?php else: ?>

               <a href="<?php echo $like_url; ?>2"><?php endif?>No</a>(<?php echo $this->htmlEscape($_review->getNotlike()) ?>)  </p>    

After that go to app\code\core\Mage\Review\controllers\ProductController.php

Add   

$customer_id = Mage::getSingleton('customer/session')->getCustomerId();

                                                $rev_id = Mage::app()->getRequest()->getParam('rev');                                                             

                                                $lik = Mage::app()->getRequest()->getParam('lik');                                        

                                                if($lik>0){                                                                            

                                                                Mage::getModel('review/resource_review')->saveLikereview($product->getId(),$rev_id,$customer_id,$lik);     

                                                }

After

public function listAction()    {                    

                                if ($product = $this->_initProduct()) {

            Mage::register('productId', $product->getId());

Now open  app\code\core\Mage\Review\Model\Resource\Review.php  and past this

public function saveLikereview($product_id,$rev_id,$customer_id,$lik)

                {

                                $adapter = $this->_getWriteAdapter();

                                if($lik==1){ $like=1; $notlike=0; }

                                elseif($lik==2){ $like=0; $notlike=1; }

                                $data = array(

                                                    'product_id'  =>  $product_id,

                                                     'review_id'        =>  $rev_id,

                                                     'customer_id'  =>           $customer_id,

                                                   'like'                     =>           $like,

                                                    'notlike'                              =>           $notlike

                                      );

                                try{

                                                $res = $adapter->insert($this->_reviewLikeTable, $data);

                                                if($res)

                                                {

                                                                $adapter1 = $this->_getReadAdapter();

                                                                $select = $adapter->select()

                                                                                ->from($this->_reviewDetailTable, array('like','notlike'))

                                                                                ->where('review_id = :review_id');

                                                                $no_rev = $adapter1->fetchAll($select, array(':review_id' => $rev_id));

                                                               

                                                                                $condition = "review_id =".$rev_id;

                                                                                $data = array(                                                                                                   

                                                                                                                  'like'                     =>           ($like + $no_rev[0]['like']),

                                                                                                                  'notlike'                              =>           ($notlike + $no_rev[0]['notlike'])

                                                                                                                  );

                    $adapter->update($this->_reviewDetailTable, $data, $condition);      

                                                }

                                }

                                catch(Exception $e){      }             

Also past  $this->_reviewLikeTable   = $this->getTable('review/review_like');  under protected function _construct()

Now open app\code\core\Mage\Review\Model\Resource\Review\Collection.php

And add $this->_reviewLikeTable     = $this->getTable('review/review_like'); under  protected function _construct()

And change array('detail_id', 'title', 'detail', 'nickname', 'customer_id')); in to

array('detail_id', 'title', 'detail', 'nickname', 'customer_id','like','notlike'));