Question

我使用多对多的关系;

用户实体;

/**
 * @ORM\ManyToMany(targetEntity="Conversation", inversedBy="users")
 */
protected $conversations;

会话实体;

/**
 * @ORM\ManyToMany(targetEntity="User", mappedBy="conversations")
 * @ORM\JoinTable(name="user_conversation")
 */
protected $users;

何时，我正在使用此功能;

$user->getConversations();

Symfony在后台使用这个sql代码;

SELECT 
  t0.id AS id1, 
  t0.conversationid AS conversationid2 
FROM 
  Conversation t0 
  INNER JOIN user_conversation ON t0.id = user_conversation.conversation_id 
WHERE 
  user_conversation.user_id = ?

并选择所有对话。这将是性能问题。所以，我使用存储库类。但是，我不能一起做多对多和限制功能。我该怎么办？我写给存储库类的内容是什么？

Answer 1

如果您想在学说中优化对大型馆藏的访问，请使用Criteria (That only works on OneToMany associations.)

实施例：

use Doctrine\ORM\Mapping as ORM;
use Doctrine\Common\Collections\Criteria;

/**
 * @ORM\Entity
 * @ORM\Table
 */
class User
{
    ....

    public function getLatestConversation()
    {
        $criteria = Criteria::create()
            ->setMaxResults(10);

        return $this->conversations->matching($criteria);
    }
}

对于ManyToMany，我认为您必须创建自定义查询：

public function getLatestConversations($user)
{
    $qb = $this->createQueryBuilder("c");
    $qb
        ->leftjoin("c.users", "u")
        ->where("u = :user")
        ->setParameter("user", $user)
        ->setMaxResults(2);

    return $qb->getQuery()->getResult();
}

Answer 2

您可以将其转换为Arraycollection对象：

$input = $repo->getConversations(); //manytomany relation
$arr = new ArrayCollection();
foreach ($input as $e){
    $arr->add($e);
}

然后在$ arr上使用你的Criteria

Answer 3

尝试

$repository = $em->getRepository('YourBundle:Conversations');
$query = $repository->createQueryBuilder('C')
       ->join('C.Users', 'U')
       ->where('U.id = :uid')
       ->setMaxResults(20) //set your amount for limit
       ->setParameter('uid', $user_id)
       ->getQuery();
$result = $query->getResults();

Symfony2 - 多对多关系和LIMIT

3 个答案: