http://chriskief.com/2012/12/17/symfony2-vs-django-models/

Blog.php

<?php

namespace NewCoInc\AppBundle\Entity;

use Doctrine\ORM\Mapping as ORM;
use Doctrine\Common\Collections\ArrayCollection;
use NewCoInc\AppBundle\Lib\FormattingLib;

/**
 * Blog
 *
 * @ORM\Table(name="blog")
 * @ORM\Entity(repositoryClass="NewCoInc\AppBundle\Entity\BlogRepository")
 */
class Blog
{
    /**
     * @var integer
     *
     * @ORM\Column(name="id", type="integer", nullable=false)
     * @ORM\Id
     * @ORM\GeneratedValue(strategy="IDENTITY")
     */
    private $id;

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

	/**
	 * @ORM\Column(type="string")
	 */
	private $slug;

    /**
     * @var string
     *
     * @ORM\Column(name="author", type="string", length=100, nullable=false)
     */
    private $author;

    /**
     * @var string
     *
     * @ORM\Column(name="blog", type="text", nullable=false)
     */
    private $blog;

    /**
     * @var string
     *
     * @ORM\Column(name="image", type="string", length=20, nullable=false)
     */
    private $image;

    /**
     * @var string
     *
     * @ORM\Column(name="tags", type="text", nullable=false)
     */
    private $tags;

	/**
	 * @ORM\OneToMany(targetEntity="Comment", mappedBy="blog")
	 */
	private $comments;

    /**
     * @var \DateTime
     *
     * @ORM\Column(name="created", type="datetime", nullable=false)
     */
    private $created;

    /**
     * @var \DateTime
     *
     * @ORM\Column(name="updated", type="datetime", nullable=false)
     */
    private $updated;

	public function __construct()
	{
		$this->comments = new ArrayCollection();

		$this->setCreated(new \DateTime());
		$this->setUpdated(new \DateTime());

		$this->formatter = new FormattingLib();
	}

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

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

		$this->setSlug($this->title);
    
        return $this;
    }

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

    /**
     * Set author
     *
     * @param string $author
     * @return Blog
     */
    public function setAuthor($author)
    {
        $this->author = $author;
    
        return $this;
    }

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

    /**
     * Set blog
     *
     * @param string $blog
     * @return Blog
     */
    public function setBlog($blog)
    {
        $this->blog = $blog;
    
        return $this;
    }

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

    /**
     * Set image
     *
     * @param string $image
     * @return Blog
     */
    public function setImage($image)
    {
        $this->image = $image;
    
        return $this;
    }

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

    /**
     * Set tags
     *
     * @param string $tags
     * @return Blog
     */
    public function setTags($tags)
    {
        $this->tags = $tags;
    
        return $this;
    }

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

    /**
     * Set created
     *
     * @param \DateTime $created
     * @return Blog
     */
    public function setCreated($created)
    {
        $this->created = $created;
    
        return $this;
    }

    /**
     * Get created
     *
     * @return \DateTime 
     */
    public function getCreated()
    {
        return $this->created;
    }

    /**
     * Set updated
     *
     * @param \DateTime $updated
     * @return Blog
     */
    public function setUpdated($updated)
    {
        $this->updated = $updated;
    
        return $this;
    }

    /**
     * Get updated
     *
     * @return \DateTime 
     */
    public function getUpdated()
    {
        return $this->updated;
    }

    /**
     * Add comments
     *
     * @param \NewCoInc\AppBundle\Entity\Comment $comments
     * @return Blog
     */
    public function addComment(\NewCoInc\AppBundle\Entity\Comment $comments)
    {
        $this->comments[] = $comments;
    
        return $this;
    }

    /**
     * Remove comments
     *
     * @param \NewCoInc\AppBundle\Entity\Comment $comments
     */
    public function removeComment(\NewCoInc\AppBundle\Entity\Comment $comments)
    {
        $this->comments->removeElement($comments);
    }

    /**
     * Get comments
     *
     * @return \Doctrine\Common\Collections\Collection 
     */
    public function getComments()
    {
        return $this->comments;
    }

    /**
     * Set slug
     *
     * @param string $slug
     * @return Blog
     */
    public function setSlug($slug)
    {
		$this->slug = $this->formatter->slugify($slug);
    
        return $this;
    }

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