我在 Resources/config/doctrine 文件夹中使用 yml-syntax 在我的 symfony 包中创建了一个实体:

Sulu\Bundle\TranslateBundle\Entity\Translation:
type: entity
table: tr_translations
id:
    code:
        type: string
        column: idCodes
        associationKey: id
    catalogue:
        type: string
        column: idCatalogues
        associationKey: id
fields:
    value:
        type: text
manyToOne:
    code:
        targetEntity: Code
        inversedBy: tr_codes
        joinColumn:
            name: idCodes
            referencedColumnName: id
    catalogue:
        targetEntity: Catalogue
        inversedBy: tr_catalogues
        joinColumn:
            name: idCatalogues
            referencedColumnName: id

这部分工作正常。但是当我像下面的代码一样创建一些对象时，我收到一条错误消息，提示我必须使用 flush 方法才能获取外键的 ID。

这是我目前使用的代码片段:

    // create a new package and catalogue for the import
    $package = new Package();
    $package->setName($this->getName());
    $catalogue = new Catalogue();
    $catalogue->setLocale($this->getLocale());
    $catalogue->setPackage($package);

    $this->em->persist($package);
    $this->em->persist($catalogue);

    // load the file, and create a new code/translation combination for every message
    $fileCatalogue = $loader->load($this->getFile(), $this->getLocale());
    foreach ($fileCatalogue->all()['messages'] as $key => $message) {
        $code = new Code();
        $code->setPackage($package);
        $code->setCode($key);
        $code->setBackend(true);
        $code->setFrontend(true);

        $translate = new Translation();
        $translate->setCode($code);
        $translate->setValue($message);
        $translate->setCatalogue($catalogue);

        $this->em->persist($code);
        $this->em->flush(); //FIXME no flush in between, if possible
        $this->em->persist($translate);
    }

    // save all the changes to the database
    $this->em->flush();

如果我不在 foreach 循环中调用 flush，我会得到以下错误，我完全理解，但是对于这个问题没有更优雅的解决方案吗？

Doctrine\ORM\ORMException : Entity of type Sulu\Bundle\TranslateBundle\Entity\Translation has identity through a foreign entity Sulu\Bundle\TranslateBundle\Entity\Code, however this entity has no identity itself. You have to call EntityManager#persist() on the related entity and make sure that an identifier was generated before trying to persist 'Sulu\Bundle\TranslateBundle\Entity\Translation'. In case of Post Insert ID Generation (such as MySQL Auto-Increment or PostgreSQL SERIAL) this means you have to call EntityManager#flush() between both persist operations.

最佳答案

不幸的是，根据 Doctrine Docs你必须调用 flush 来获取外键的 ID:

Generated entity identifiers / primary keys are guaranteed to be available after the next successful flush operation that involves the entity in question. You can not rely on a generated identifier to be available directly after invoking persist. The inverse is also true. You can not rely on a generated identifier being not available after a failed flush operation.

关于php - 在学说中坚持具有两个外国身份的对象，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/18143630/