@ UniqueEntity

Test.php

use Doctrine\ORM\Mapping as ORM;
use Doctrine\Common\Collections\ArrayCollection;
use Symfony\Bridge\Doctrine\Validator\Constraints\UniqueEntity;
use Symfony\Component\Validator\Constraints as Assert;
use Symfony\Component\Validator\ExecutionContextInterface;

use Knp\DoctrineBehaviors\Model as ORMBehaviors;

/**
 * @ORM\Table("Test")
 * @ORM\Entity(repositoryClass="Charly\TestBundle\Entity\TestRepository")
 * @ORM\HasLifecycleCallbacks
 * @UniqueEntity("reference")
 */
class Test
{
	
	/**
	 * @Assert\NotBlank()
	 * @ORM\Column(type="string", length=255, unique=true)
	 */
	private $reference;

}