php - 在 Symfony 项目上使用 "Class Table Inheritance"加入 Doctrine 太多

Question

我在使用 Symfony 和 Doctrine 时遇到了以下错误:

SQLSTATE[HY000]: General error: 1116 Too many tables; MySQL can only use 61 tables in a join`

主要实体(层次结构的最顶层表)包含超过 61 个实体的鉴别器映射。 “多对多”关联是建立在自身之上的，因此实体可以作为父实体或子实体与其他实体关联。

这是实体 Doctrine 注释:

/**
 * Entity
 *
 * @ORM\Table(name="entity")
 * @ORM\Entity(repositoryClass="Acme\EntityBundle\Repository\EntityRepository")
 * @InheritanceType("JOINED")
 * @DiscriminatorColumn(name="type", type="string")
 * @DiscriminatorMap({
 *      "sub_entity_1" = "\Acme\SubEntityABundle\Entity\E1",
 *      "sub_entity_2" = "\Acme\SubEntityABundle\Entity\E2",
 *      ...
 * })
 */
class Entity
{
    /**
     * @ORM\ManyToMany(targetEntity="Entity", inversedBy="parentEntities")
     * @ORM\JoinTable(name="rel_entity_entity",
     *   joinColumns={@ORM\JoinColumn(name="parent", referencedColumnName="id")},
     *   inverseJoinColumns={@ORM\JoinColumn(name="child", referencedColumnName="id")}
     * )
     */
    private $childrenEntities;

    /**
     * @ORM\ManyToMany(targetEntity="Entity", mappedBy="childrenEntities")
     *
     */
    private $parentEntities;

    /**
     * Get children entities
     *
     * @return \Doctrine\Common\Collections\Collection
     */
    public function getChildrenEntities()
    {
        return $this->childrenEntities;
    }

    /**
     * Set childrenEntities
     *
     * @param ArrayCollection $entities
     */
     public function setchildrenEntities(ArrayCollection $entities)
     {
         $this->childrenEntities = $entities;
     }

     ...
}

每当我在 formType 中使用查询构建器来获取一些经典实体的列表(它们甚至不扩展顶级“实体”)时，Doctrine 将对鉴别器映射中的每个实体进行左连接(并生成MySQL的一般错误)。

表单类型:

public function buildForm(FormBuilderInterface $builder, array $options)
{
    $builder->add('childrenEntities', 'entity', array(
        'class' => 'AcmeEntityBundle:Entity',
        'required' => false,
        'choice_label' => 'slug', // slug is defined as a main entity's attribute
        'query_builder' => function (EntityRepository $er) {
            return $er->getSomeEntities();
        },
    ));

    ...
}

实体库:

public function getSomeEntities()
{
    return $this->getEntityManager()
        ->createQueryBuilder()
        ->select('e')
        ->from('AcmeEntityBundle:Entity', 'e')
        ->where('e.id IN (:ids)')
        // Tried that, doesn't work
        //->andWhere('e INSTANCE OF AcmeEntityBundle:Entity')
        ->setParameter('ids', [53300, 12345]);
}

有没有办法告诉 doctrine 不要做任何连接？我只需要主实体的属性，例如 id 或 slug，所以我不需要子类的任何值

Doctrine 版本是:2.4

我阅读的一些有用的文档:

• Query field of root entity in doctrine (joined) class table inheritance
• Doctrine2: Arbitrary join and single table inheritance
• http://doctrine-orm.readthedocs.io/projects/doctrine-orm/en/latest/reference/inheritance-mapping.html#class-table-inheritance

谢谢!

Answer 1

嗯，大问题，因为是 mysql limitation .如果您不要求，我不明白为什么 Doctrine 要进行左连接。如果您只需要与主要实体相关的数据，他们会将选择更改为那些特定字段:

->select('e.id, e.slug, ...')

希望对你有帮助。