Replace object for null in form symfony2

Question

I have a similar problem to this: Replace an object with Null value Using Form Builder in Symfony2

I have an entity called Classification that has a ManyToOne Relationship to another entity called TypeClassification (one Classification belong to one type classification, or to none typeclassfication).

Classification.php:

 /**
 * @ORM\ManyToOne(targetEntity="TypeClassification", inversedBy="classifications", fetch="EAGER")
 */
private $typeclassification;

TypeClassification.php:

/**
 * @ORM\OneToMany(targetEntity="Classification", mappedBy="typeclassification")
 */
private $classifications;

The form for Classification generated by default by symfony works, here is the code:

public function buildForm(FormBuilderInterface $builder, array $options)
{
    $builder
        ->add('name')
        ->add('namejapanese')
        ->add('ldapid')
        ->add('typeclassification','entity', array('class' => 'ACMEMyBundle:TypeClassification','required' => false));
}

My problem relies in the entity choice field. I would like to allow Null value, and to set the relationship to Null.

As I said it works so far, but as soon as I add validation constraints to the Entity Classification, even if they are not related to the relationship at all:

validation.yml:

ACME\MyBundle\Entity\Classification:
#If I commend this constraints, everything works properly.
constraints:    
    - Symfony\Bridge\Doctrine\Validator\Constraints\UniqueEntity: { fields: name, message: unique.name }
    - Symfony\Bridge\Doctrine\Validator\Constraints\UniqueEntity: { fields: ldapid, message: unique.ldapid }
#For this properties doesn't matter if they are here or not
properties: 
    name:
        - NotBlank:
            message: not.blank
    namejapanese:
        - NotBlank:
            message: not.blank
    ldapid:
        - NotBlank:
            message: not.blank

Then I am unable to set the relationship back to Null. but If I comment the constraints part, then I can set it back to Null.

Why does that happen? And How can I make it to have both this validation and the ability to set the relationship to Null?

Answer 1

That's because UniqueEntity constraint validator, which treats null's as duplicates. Create your own validator service and do checks there.