我有两个通过 OneToMany 关系关联的实体：
<?php
namespace CRMBundle\Entity;
use Doctrine\Common\Collections\ArrayCollection;
use Doctrine\ORM\Mapping as ORM;
use Symfony\Component\Validator\Constraints as Assert;
/**
* User
*
* @ORM\Table()
* @ORM\Entity(repositoryClass="CRMBundle\Entity\ContactRepository")
*/
class User
{
/*...*/
/**
* @ORM\OneToMany(targetEntity="CRMBundle\Entity\Message", mappedBy="user", cascade={"persist"})
* @ORM\OrderBy({"datetime" = "DESC"})
*/
protected $messages;
/*...*/
}
和
<?php
namespace CRMBundle\Entity;
use Doctrine\ORM\Mapping as ORM;
/**
* Message
*
* @ORM\Table()
* @ORM\Entity
*/
class Message
{
/*...*/
/**
* @ORM\ManyToOne(targetEntity="CRMBundle\Entity\User", inversedBy="messages")
* @ORM\JoinColumn(name="user_id", referencedColumnName="id", onDelete="SET NULL")
*/
private $user;
/**
* @var \DateTime …