Question

有两个实体 - Asset和Attachment，双向映射OneToOne。每个Asset 都可以 0..1 Asset：

Asset

class Asset
{
    /**
     * @var string @ORM\Column(name="asset_uuid", type="string", length=36, nullable=false)
     *      @ORM\Id
     */
    private $uuid;
    /**
     * @var \MyLib\Model\Entity\Attachment
     * @ORM\OneToOne(targetEntity="MyLib\Model\Entity\Attachment", mappedBy="asset", cascade={"remove", "persist"}, orphanRemoval=true)
     **/
    private $attachment;
    ...
}

Attachment

class Attachment
{
    /**
     * @var string @ORM\Column(name="attachment_uuid", type="string", length=36, nullable=false)
     *      @ORM\Id
     */
    private $uuid;
    /**
     * @var \MyLib\Model\Entity\Asset
     * @ORM\OneToOne(targetEntity="\MyLib\Model\Entity\Asset", inversedBy="attachment", cascade={"persist"})
     * @ORM\JoinColumn(name="attachment_linkassetuuid", referencedColumnName="asset_uuid")
     */
    private $asset;
    ...
}

现在我要find() Attachment Asset.uuid来class AssetService ... { ... private function finAttachmentByAssetUuid($assetUuid) { $entityManager = $this->getEntityManager(); $attachmentRepository = $entityManager->getRepository('MyLib\Model\Entity\Attachment'); $attachment = $attachmentRepository->findBy([ 'attachment_linkassetuuid' => $assetUuid ]); return $attachment; } ... }：

Doctrine\Common\Persistence#findBy(...)

但它没有并且无法工作，因为Doctrine需要一个实体属性名称，而不是表列名。好吧，但是这里实体没有外键列的属性。

在这种情况下如何使用Attachment？或者，如果不可能：如何在此Asset.uuid中检索// Dont forget the "http://". A lot of browser add it themselves but the WebClient doesnt. string remoteUri = "download.finance.yahoo.com/d/quotes.csv?s=%40%5EDJI,aapl&f=o&e=.csv"; // I recommend to take the habitude to write each one in one line. string fileName = "aapl.csv", myStringWebResource = null; // Use the "using" keyword to dispose WebClient WebClient myWebClient = new WebClient(); // Why are you doing this? Your url is working without. No need to concat here. myStringWebResource = remoteUri + fileName; // Download the Web resource and save it into the current filesystem folder. myWebClient.DownloadFile(myStringWebResource, fileName);具体案例的另一种方式？

Answer 1

在Doctrine中，重点是您的实体，而不是您的数据库结构。因此，如果您想获得一个关联实体，您将无法通过外部ID获取它，而是获得相关实体。如果您不希望Doctrine执行查询来执行此操作，您可以获得对此实体的引用：

/** @var EntityManager $em */
$asset = $em->getReference('MyLib\Model\Entity\Asset', $assetId);
$attachement = $asset->getAttachment();

您可以阅读doctrine internals文档中的参考文献：

http://doctrine-orm.readthedocs.org/en/latest/reference/unitofwork.html

如何使用findBy（$ creteria）进行双向OneToOne映射？

1 个答案: