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Question

我正在使用symfony 3.1.10制作的项目。

我有三个实体

MyEntity 1-> n MyPivotEntity

MyPivotEntity n-> 1 MySuperInheritanceEntity

，我还有另一个实体MyInheritanceEntity，它从具有单表继承的MySuperInheritanceEntity继承

https://www.doctrine-project.org/projects/doctrine-orm/en/2.6/reference/inheritance-mapping.html#single-table-inheritance

我以MyEntityType形式创建了MyPivotEntity的CollectionType字段，但是当我从控制器创建createForm时，我收到了一条内存超出消息，因为构建器为每个MySuperInheritanceEntity进行了数据库请求。我该如何预防？在这种情况下，我根本不需要MySuperInheritanceEntity信息，只需要MyPivotEntity字段

<?php 

/**
 * MyEntity
 *
 * @ORM\Table(name="my_entity")
 * @ORM\Entity()
 */
class MyEntity {
    /**
     * @ORM\OneToMany(targetEntity="MyPivotEntity", mappedBy="myEntity", cascade={"persist"})
     */
    private $myPivotEntity;
}

/**
 * MyPivotEntity
 *
 * @ORM\Table(name="my_pivot_entity")
 * @ORM\Entity()
 */
class MyPivotEntity {
    /**
     * @ORM\ManyToOne(targetEntity="MyEntity", inversedBy="myPivotEntity", cascade={"persist"})
     */
    private $myEntity;

    /**
     * @ORM\ManyToOne(targetEntity="MySuperInheritanceEntity", inversedBy="myPivotEntity", cascade={"persist"})
     */
    private $mySuperInheritanceEntity;
}

/**
 * MySuperInheritanceEntity
 *
 * @ORM\Table(name="my_super_inheritance_entity")
 * @ORM\Entity()
 * @ORM\InheritanceType("SINGLE_TABLE")
 */
class MySuperInheritanceEntity {
    /**
     * @ORM\OneToMany(targetEntity="MyPivotEntity", mappedBy="mySuperInheritanceEntity")
     */
    private $myPivotEntity;
}

/**
 * MyInheritanceEntity
 *
 * @ORM\Table(name="my_inheritance_entity")
 * @ORM\Entity()
 */
class MyInheritanceEntity extends MySuperInheritanceEntity {

}

class MyEntityType extends AbstractType
{
    /**
     * {@inheritdoc}
     */
    public function buildForm(FormBuilderInterface $builder, array $options)
    {
        $builder
            ->add('myPivotEntity', CollectionType::class, [
                'entry_type' => MyPivotEntityType::class
            ]);
    }
}


class MyPivotEntityType extends AbstractType
{
    /**
     * {@inheritdoc}
     */
    public function buildForm(FormBuilderInterface $builder, array $options)
    {
        $builder
            ->add('somField');
    }
}

class MyController extends Controller {
    /**
     * @Post("/myEntity/update")
     */
    public function postMyEntityUpdateAction(Request $request, MyEntity $myEntity) {
        $form = $this->createForm(MyEntityType::class, $myEntity);

        // here error 500 because of too mach memory
        // caused by the MyPivotEntityType wich runs a request for each entry,
        // trying to retrive all the information about MySuperInheritanceEntity and MyInheritanceEntity
        // even if I don't need it at all
        // because of the @ORM\InheritanceType("SINGLE_TABLE")
        // deleting the inheritance solves the problem, but I need it

        $form->handleRequest($request);

        if ($form->isValid()) {
            $this->getEm()->flush();
            return ['success' => true];
        }

        $errors = (string) $form->getErrors(true, false);
        throw new HttpException(400, $errors);
    }
}

Answer 1

文档says：

关于单表继承有一个一般的性能考虑：如果目标实体是多对一或一对一关联是STI实体，出于性能考虑，它最好是继承层次结构中的叶实体（即没有子类）。

还请记住：

为OneToMany关联属性名称使用复数名称：

class MyEntity {
        /**
         * @ORM\OneToMany(targetEntity="MyPivotEntity", mappedBy="myEntity", cascade={"persist"})
         */
        private $myPivotEntities;
}

更新

作为一种替代方法，您可能会完全忘记继承，并拥有复制了所有属性和关联的单独的（以前是子级的）实体。

Symfony-与父实体的Doctrine单表继承ManyToOne关联

1 个答案:

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