doctrine：ManyToOne：该字段以NULL值插入到DB中

Question

我在两个字段 personnelLanguages（类Personnel）和人员（类LanguagesPersonnel）之间建立了关系OneToMany，问题是在插入中我有字段personnel_id = personnel_languages表中的NULL：

   id   personnel_id    level   language
    7   NULL                5         5
    8   NULL                5         1 

实体：

人员实体：

/**
 * Personnel
 *
 * @ORM\Table(name="personnel")
 * @ORM\Entity(repositoryClass="HomeBundle\Repository\PersonnelRepository")
 */
class Personnel
{
    // some fields 
    /**
      * @var collection
      * @ORM\OneToMany(targetEntity="PersonnelLanguages" , mappedBy="personnel" , cascade={"all"})
      */
    private $personnelLanguages;


    public function __construct()
    {
        $this->personnelLanguages = new ArrayCollection(array(new PersonnelLanguages(),new PersonnelLanguages()) );
    }
    // getters and setters


    /**
     * @return collection
     */
    public function getPersonnelLanguages()
    {
        return $this->personnelLanguages;
    }

    /**
     * @param collection $personnelLanguages
     *
     * @return self
     */
    public function setPersonnelLanguages(collection $personnelLanguages)
    {
        $this->personnelLanguages = $personnelLanguages;

        return $this;
    }
}

PersonnelLanguages实体：

/**
 * PersonnelLanguages
 *
 * @ORM\Table(name="personnel_languages")
 * @ORM\Entity(repositoryClass="HomeBundle\Repository\PersonnelLanguagesRepository")
 */
 class PersonnelLanguages{
    /**
     * @var int
     *
     * @ORM\Column(name="id", type="integer")
     * @ORM\Id
     * @ORM\GeneratedValue(strategy="AUTO")
     */
    private $id;

    /**
    * @var int
    *
    * @ORM\ManyToOne(targetEntity="Personnel", inversedBy="personnelLanguages")
    * @ORM\JoinColumn(name="personnel_id", referencedColumnName="id")
    */
    private $personnel;

    /**
     * @var string
     *
     * @ORM\Column(name="language", type="string", length=50, nullable=true)
     */
    private $language;

    /**
     * @var string
     *
     * @ORM\Column(name="level", type="string", length=50, nullable=true)
     */
    private $level;
    // getters and setters
}

**表格**：

PersonnelType：

->add("personnelLanguages",CollectionType::class, array(
            'entry_type' => PersonnelLanguagesType::class,
            'entry_options' => array("label"=>false),
            'allow_add' => true,
            'allow_delete' => true,
        ))

因此，当我创建一个包含personnelLanguages字段的新Personnel时，我在employees_languages表中为personnel_id设置了NULL值。

一个想法：可能因为在创建的那一刻，personnel_id不存在!!!

调试：

我调试了这个动作，我发现这两个 print_r ，人员对象中的 id 不存在，直到 die

教条应该自动管理这个问题还是我的代码有问题？

public function newAction(Request $request)
    {
        $personnel = new Personnel();
        $form = $this->createForm('HomeBundle\Form\PersonnelType', $personnel);
        $form->handleRequest($request);

        if ($form->isSubmitted() && $form->isValid()) {
            print_r($personnel->getId()); echo "--";
            print_r($personnel->getpersonnelLanguages()); die;

            $em = $this->getDoctrine()->getManager();
            $em->persist($personnel);
            $em->flush();

            return $this->redirectToRoute('personnel_show', array('id' => $personnel->getId()));
        }