學說：急於加載一個懶惰的關係的關係？

Question

我正在使用Doctrine 2來映射學術計劃。這裏有一個簡單看關係：

• 一個類有事件（一到多）
  • 的事件有型（多到一）
  • 一種事件具有位置（多到一個）

使用$em->find()我只能使用惰性加載關係獲取類。或者在連接中使用DQL，我可以加載整個對象圖。中間是否有解決方案？

我想偷懶加載關係去取類，然後在一定條件下觸發事件關係的渴望負荷和所有事件性能。所以，當我打電話像$class->getEventsHydrateAll()，所有事件和事件類型和事件地點將被立即水合。

我想我可以通過更新我的事件架構標誌型和位置關係，因爲fetch="EAGER"做到這一點。但是我想要控制這種深度水合作用發生的時間。

這裏有一個嘗試我在類資源庫做了，但原則是運行單個查詢查找每個型和位置。

$query = $this->_em->createQuery(' 
     SELECT c FROM My\Entity\Class c 
     WHERE c.id = :classId 
'); 
$query->setParameter('classId', $classId) 
     ->setFetchMode('My\Entity\Event', 'type', 'EAGER') 
     ->setFetchMode('My\Entity\Event', 'location', 'EAGER'); 

try { 
    return $query->getSingleResult(); 
} catch (\Doctrine\ORM\NoResultException $e) { 
    return NULL; 
} 

有沒有人知道是否Doctrine支持這個？謝謝！

Answer 1

我不確定，但我認爲getSingleResult會覆蓋水合模式。

嘗試「執行」來代替，如本例所示：http://docs.doctrine-project.org/en/latest/reference/dql-doctrine-query-language.html#dql-temporarily-change-fetch-mode

Answer 2

TL; DR：

您可以使用EAGER標誌上的類屬性有它加載它的關係熱切。 http://doctrine-orm.readthedocs.org/en/latest/reference/annotations-reference.html#manytoone

我不確定這是否會對您有幫助，但這是我解決問題的方法。

首先介紹一下我的情況。我目前正在創建一個OAuth 2實現，我希望在該範圍內對其進行細粒度控制。作用域非常精細（例如電子郵件地址，用戶名等），然後您可以爲它們分別設置各自的權限，以便讀取，創建，編輯和刪除。

下面是一個數據庫圖表鬆散表明關係：

所以我的問題是，如何我舉個例子，看看如果一個特定的標記允許閱讀（許可）一用戶名（範圍）？

如果我加載令牌，然後得到它的所有權限，那麼的foreach 閱讀允許，我檢查了用戶名範圍，那麼這是一個很大的數據庫訪問。

測試代碼：

$permissions = $this->getOAuthHelper() 
        ->getAccessToken($accessToken) 
        ->getPermissions(); 
$results = []; 
foreach ($permissions as $permission) { 
    $results[] = $permission->getScope()->getTitle(); 
} 
return $results; 

查詢日誌：

150630 10:49:47 54 Connect root@localhost on api 
150630 10:49:51 54 Query  SELECT t0.id AS id1, t0.token AS token2, t0.token_expiration AS token_expiration3, t0.refresh AS refresh4, t0.created_at AS created_at5, t0.deleted_at AS deleted_at6, t0.user_id AS user_id7, t0.client_id AS client_id8 FROM oauth_access_tokens t0 WHERE t0.token = 'user-test-token' LIMIT 1 
        54 Query  SELECT t0.id AS id1, t0.access_permission AS access_permission2, t0.scope_id AS scope_id3 FROM oauth_permissions t0 INNER JOIN oauth_access_to_permissions ON t0.id = oauth_access_to_permissions.permission_id WHERE oauth_access_to_permissions.access_id = '1' 
150630 10:49:52 54 Query  SELECT t0.id AS id1, t0.title AS title2, t0.brief AS brief3, t0.category_id AS category_id4 FROM oauth_scopes t0 WHERE t0.id = '1' 
        54 Query  SELECT t0.id AS id1, t0.title AS title2, t0.brief AS brief3, t0.category_id AS category_id4 FROM oauth_scopes t0 WHERE t0.id = '2' 
        54 Query  SELECT t0.id AS id1, t0.title AS title2, t0.brief AS brief3, t0.category_id AS category_id4 FROM oauth_scopes t0 WHERE t0.id = '3' 
        54 Query  SELECT t0.id AS id1, t0.title AS title2, t0.brief AS brief3, t0.category_id AS category_id4 FROM oauth_scopes t0 WHERE t0.id = '4' 
        54 Query  SELECT t0.id AS id1, t0.title AS title2, t0.brief AS brief3, t0.category_id AS category_id4 FROM oauth_scopes t0 WHERE t0.id = '5' 
        54 Query  SELECT t0.id AS id1, t0.title AS title2, t0.brief AS brief3, t0.category_id AS category_id4 FROM oauth_scopes t0 WHERE t0.id = '6' 
        54 Query  SELECT t0.id AS id1, t0.title AS title2, t0.brief AS brief3, t0.category_id AS category_id4 FROM oauth_scopes t0 WHERE t0.id = '7' 
        54 Query  SELECT t0.id AS id1, t0.title AS title2, t0.brief AS brief3, t0.category_id AS category_id4 FROM oauth_scopes t0 WHERE t0.id = '8' 
        54 Query  SELECT t0.id AS id1, t0.title AS title2, t0.brief AS brief3, t0.category_id AS category_id4 FROM oauth_scopes t0 WHERE t0.id = '9' 
        54 Query  SELECT t0.id AS id1, t0.title AS title2, t0.brief AS brief3, t0.category_id AS category_id4 FROM oauth_scopes t0 WHERE t0.id = '10' 
        54 Query  SELECT t0.id AS id1, t0.title AS title2, t0.brief AS brief3, t0.category_id AS category_id4 FROM oauth_scopes t0 WHERE t0.id = '11' 
        54 Query  SELECT t0.id AS id1, t0.title AS title2, t0.brief AS brief3, t0.category_id AS category_id4 FROM oauth_scopes t0 WHERE t0.id = '12' 
        54 Query  SELECT t0.id AS id1, t0.title AS title2, t0.brief AS brief3, t0.category_id AS category_id4 FROM oauth_scopes t0 WHERE t0.id = '13' 
        54 Quit 

但是，我們可以在這裏看到的這大部分是收集連接到的權限範圍。我們可以用渴望標誌的關係從權限範圍與權限搶範圍：

/** 
* @var Scope 
* 
* @ORM\ManyToOne(targetEntity="OAuthScope", fetch="EAGER") 
* @ORM\JoinColumns({ 
* @ORM\JoinColumn(name="scope_id", referencedColumnName="id") 
* }) 
*/ 
protected $scope; 

注意fetch="EAGER"旗ManyToOne註釋。

現在，如果我們運行完全相同的代碼：

150630 11:00:06 55 Connect root@localhost on api 
150630 11:00:10 55 Query  SELECT t0.id AS id1, t0.token AS token2, t0.token_expiration AS token_expiration3, t0.refresh AS refresh4, t0.created_at AS created_at5, t0.deleted_at AS deleted_at6, t0.user_id AS user_id7, t0.client_id AS client_id8 FROM oauth_access_tokens t0 WHERE t0.token = 'user-test-token' LIMIT 1 
150630 11:00:11 55 Query  SELECT t0.id AS id1, t0.access_permission AS access_permission2, t0.scope_id AS scope_id3, t4.id AS id5, t4.title AS title6, t4.brief AS brief7, t4.category_id AS category_id8 FROM oauth_permissions t0 LEFT JOIN oauth_scopes t4 ON t0.scope_id = t4.id INNER JOIN oauth_access_to_permissions ON t0.id = oauth_access_to_permissions.permission_id WHERE oauth_access_to_permissions.access_id = '1' 
        55 Quit