BasePage setup for Doctrine2 Table Inheritance. Shows Content from same bundle and FrontPage from a separate Bundle.

BasePage.php

<?php

namespace Manhattan\Bundle\ContentBundle\Entity;

use Doctrine\ORM\Mapping as ORM;

/**
 * Manhattan\Bundle\ContentBundle\Entity\BasePage
 *
 * @ORM\Table(name="base_page")
 * @ORM\Entity
 * @ORM\HasLifecycleCallbacks
 * @ORM\InheritanceType("JOINED")
 * @ORM\DiscriminatorColumn(name="class_name", type="string")
 * @ORM\DiscriminatorMap({
 * "content" = "Content", 
 * "other_content" = "Manhattan\Bundle\OtherBundle\Entity\FrontPage"
 * })
 */
abstract class BasePage
{
    /**
     * @var integer $id
     *
     * @ORM\Column(name="id", type="integer")
     * @ORM\Id
     * @ORM\GeneratedValue(strategy="AUTO")
     */
    private $id;

    /**
     * @var string $meta_description
     *
     * @ORM\Column(name="meta_description", type="string", length=500)
     */
    private $meta_description;

    /**
     * @var string $html_title
     *
     * @ORM\Column(name="html_title", type="string", length=255)
     */
    private $html_title;

    /**
     * @var datetime $created_at
     *
     * @ORM\Column(name="created_at", type="datetime")
     */
    private $created_at;

    /**
     * @var datetime $updated_at
     *
     * @ORM\Column(name="updated_at", type="datetime")
     */
    private $updated_at;


    /**
     * Get id
     *
     * @return integer 
     */
    public function getId()
    {
        return $this->id;
    }

    /**
     * Set meta_description
     *
     * @param string $metaDescription
     */
    public function setMetaDescription($metaDescription)
    {
        $this->meta_description = $metaDescription;
    }

    /**
     * Get meta_description
     *
     * @return string 
     */
    public function getMetaDescription()
    {
        return $this->meta_description;
    }

    /**
     * Set html_title
     *
     * @param string $htmlTitle
     */
    public function setHtmlTitle($htmlTitle)
    {
        $this->html_title = $htmlTitle;
    }

    /**
     * Get html_title
     *
     * @return string 
     */
    public function getHtmlTitle()
    {
        return $this->html_title;
    }

    /**
     * Set created_at
     *
     * @param datetime $createdAt
     */
    public function setCreatedAt(\DateTime $createdAt)
    {
        $this->created_at = $createdAt;
    }

    /**
     * Get created_at
     *
     * @return datetime 
     */
    public function getCreatedAt()
    {
        return $this->created_at;
    }

    /**
     * Set updated_at
     *
     * @param datetime $updatedAt
     */
    public function setUpdatedAt(\DateTime $updatedAt)
    {
        $this->updated_at = $updatedAt;
    }

    /**
     * Get updated_at
     *
     * @return datetime 
     */
    public function getUpdatedAt()
    {
        return $this->updated_at;
    }

    /**
     * @orm:prePersist
     */
    public function prePersist() {
        $this->setCreatedAt(new \DateTime());
        $this->setUpdatedAt(new \DateTime());
    }
    
    /**
     * @orm:preUpdate
     */
    public function preUpdate() {
        $this->setUpdatedAt(new \DateTime());
    }

}

Content.php

<?php

namespace Manhattan\Bundle\ContentBundle\Entity;

use Doctrine\ORM\Mapping as ORM;

/**
 * Manhattan\Bundle\ContentBundle\Entity\Content
 *
 * @ORM\Table(name="content")
 * @ORM\Entity(repositoryClass="Manhattan\Bundle\ContentBundle\Entity\ContentRepository")
 */
class Content extends Page
{
    /**
     * @var string $title
     *
     * @ORM\Column(name="title", type="string", length=255)
     */
    private $title;

    /**
     * @var text $body
     *
     * @ORM\Column(name="body", type="text")
     */
    private $body;

    /**
     * Set title
     *
     * @param string $title
     */
    public function setTitle($title)
    {
        $this->title = $title;
    }

    /**
     * Get title
     *
     * @return string 
     */
    public function getTitle()
    {
        return $this->title;
    }

    /**
     * Set body
     *
     * @param text $body
     */
    public function setBody($body)
    {
        $this->body = $body;
    }

    /**
     * Get body
     *
     * @return text 
     */
    public function getBody()
    {
        return $this->body;
    }
}

FrontPage.php

<?php

namespace Manhattan\Bundle\OtherBundle\Entity;

use Doctrine\ORM\Mapping as ORM;
use Manhattan\Bundle\ContentBundle\Entity\BasePage;

/**
 * Manhattan\Bundle\OtherBundle\Entity\FrontPage
 *
 * @ORM\Table(name="front_page")
 * @ORM\Entity(repositoryClass="Manhattan\Bundle\OtherBundle\Entity\FrontPageRepository")
 */
class FrontPage extends BasePage
{
    /**
     * @var string $title
     *
     * @ORM\Column(name="title", type="string", length=255)
     */
    private $title;

    /**
     * Set title
     *
     * @param string $title
     */
    public function setTitle($title)
    {
        $this->title = $title;
    }

    /**
     * Get title
     *
     * @return string 
     */
    public function getTitle()
    {
        return $this->title;
    }

}