Symfony4 Doctrine2沒有加入

Question

我試圖獲取帶有Thread對象的Reply對象。

Thread.php

class Thread
{
    /**
    * One thread can have many replies. This is the inverse side.
    * @ORM\OneToMany(targetEntity="Reply", mappedBy="thread")
    */
    private $replies;

    public function __construct()
    {
        $this->replies = new ArrayCollection();
    }

    /**
    * @return Collection|Reply[]
    */
    public function getReplies(): Collection
    {
        return $this->replies;
    }
}

Reply.php

class Reply
{
    /**
    * @ORM\Column(type="integer")
    */
    private $thread_id;

    /**
    * Many replies have one thread. This is the owning side.
    * @ORM\ManyToOne(targetEntity="Thread", inversedBy="replies", fetch="EAGER")
    * @ORM\JoinColumn(name="thread_id", referencedColumnName="id")
    */
    private $thread;

ThreadController.php

class ThreadController extends Controller
{
    /**
    * @Route("/thread/{id}")
    */
    public function read($id)
    {
        $thread = $this->getDoctrine()->getRepository(Thread::class)->find($id);

        dump($thread); // or dump($thread->getReplies());
    }
}

但是由於某種原因，它不起作用。 Thread對象中的ArrayCollection為空並且#initialized：false。 沒關系，財產是私有的還是公共的。

來自Symfony Profiler的主義查詢，其中沒有JOIN：

SELECT 
  t0.id AS id_1, 
  t0.user_id AS user_id_2, 
  t0.title AS title_3, 
  t0.body AS body_4, 
  t0.created_at AS created_at_5, 
  t0.updated_at AS updated_at_6 
FROM 
  thread t0 
WHERE 
  t0.id = ?

哪里可能有問題？ 謝謝

Answer 1

Docctrine不會自動獲取相關對象，除非您明確嘗試訪問它們。 https://symfony.com/doc/current/doctrine/associations.html#fetching-related-objects

實際上，調用$thread->getReplies()會發出第二個請求以獲取與該線程相關的答復。

另一種解決方案是在實體存儲庫中定義一個自定義方法，並顯式聯接兩個表。

這是Symfony文檔中的一個示例

// src/Repository/ProductRepository.php
public function findOneByIdJoinedToCategory($productId)
{
    return $this->createQueryBuilder('p')
        // p.category refers to the "category" property on product
        ->innerJoin('p.category', 'c')
        // selects all the category data to avoid the query
        ->addSelect('c')
        ->andWhere('p.id = :id')
        ->setParameter('id', $productId)
        ->getQuery()
        ->getOneOrNullResult();
}

https://symfony.com/doc/current/doctrine/associations.html#joining-related-records