View CleanAssociationsTrait.php
<?php
use Doctrine\ORM\Mapping as ORM;
use Doctrine\ORM\Event\LifecycleEventArgs;
/**
* Trait CleanAssociationsTrait
*
* This trait is intended to fix the Doctrine ManyToOne relationships when the stored value in database is a 0 instead of NULL.
* Sometimes you plug Doctrine on an existing database without foreign key support.