title: doctrine 2, how do get data from the inverse side (many to one)
body: <p>I have two entities, entry and comments.</p>
  
  <p>comments:</p>
  
  <pre><code>/**
   * @Entity(repositoryClass="\Entities\Blog\CommentRepository")
   * @Table(name="blog_comment")
   * @HasLifecycleCallbacks
   */
  class Comment extends \Entities\AbstractEntity
  {
      /**
       * @Id @Column(name="id", type="integer")
       * @GeneratedValue(strategy="AUTO")
       */
      protected $id;
  
      /**
       * @ManyToOne(targetEntity="Entry", inversedBy="comments")
       * @JoinColumn(name="entry_id", referencedColumnName="id")
       */
      protected $entry;
  
      /** @Column(name="approved", type="string", length=255) */
      protected $approved;
  
      /** @Column(name="title", type="string", length=255) */
      protected $title;
  
      /** @Column(name="content", type="text") */
      protected $content;
  
      /** @Column(name="pub_date", type="datetime") */
      protected $pub_date;
  
      /** @Column(type="datetime") */
      private $created_at;
  
      /** @Column(type="datetime") */
      private $updated_at;
  
      /** @PreUpdate */
      public function updated()
      {
          $this-&gt;updated_at = new \DateTime("now");
      }
  
      public function __construct()
      {
          $this-&gt;created_at = $this-&gt;updated_at = new \DateTime("now");
      }
  }
  
  class CommentRepository extends \Entities\PaginatedRepository
  {
      protected $_entityClassName = 'Entities\Blog\Comment';
  }
  </code></pre>
  
  <p>and entry:</p>
  
  <pre><code>&lt;?php
  namespace Entities\Blog;
  
  /**
   * @Entity(repositoryClass="\Entities\Blog\EntryRepository")
   * @Table(name="blog_entry")
   * @HasLifecycleCallbacks
   */
  class Entry extends \Entities\AbstractEntity
  {
      /**
       * @Id @Column(name="id", type="integer")
       * @GeneratedValue(strategy="AUTO")
       */
      protected $id;
  
      /** @Column(name="permalink", type="string", length=255) */
      protected $permalink;
  
      /** @Column(name="title", type="string", length=255) */
      protected $title;
  
      /** @Column(name="pub_date", type="datetime") */
      protected $pub_date;
  
      /** @Column(name="content", type="text") */
      protected $content;
  
      /** @OneToMany(targetEntity="Comment", mappedBy="entry") */
      protected $comments;
  
      /** @Column(type="datetime") */
      private $created_at;
  
      /** @Column(type="datetime") */
      private $updated_at;
  
      /** @PreUpdate */
      public function updated()
      {
          $this-&gt;updated_at = new \DateTime("now");
      }
  
      public function __construct()
      {
          $this-&gt;comments = new \Doctrine\Common\Collections\ArrayCollection();
      }
  </code></pre>
  
  <p>I can get the collection of all comments belonging to each entry via:</p>
  
  <pre><code>foreach ($comments as $comment){
     $comment-$commentId;
  }
  </code></pre>
  
  <p>but how can I get the entry information from the comments side. for example, I would like to get the entry id from a specific comment</p>