奏鸣曲3:删除OneToMany关系中的实体不适用于'by_reference‘=> false

// 实体类
class EntityA
{
    /**
     * @ORM\OneToMany(targetEntity="EntityB", mappedBy="entityA", cascade={"persist"})
     */
    private $entityBs;

    public function __construct()
    {
        $this->entityBs = new ArrayCollection();
    }

    public function addEntityB(EntityB $entityB)
    {
        $this->entityBs[] = $entityB;
        $entityB->setEntityA($this);
    }

    public function removeEntityB(EntityB $entityB)
    {
        $this->entityBs->removeElement($entityB);
        $entityB->setEntityA(null);
    }
}

class EntityB
{
    /**
     * @ORM\ManyToOne(targetEntity="EntityA", inversedBy="entityBs")
     * @ORM\JoinColumn(name="entity_a_id", referencedColumnName="id")
     */
    private $entityA;

    public function getEntityA()
    {
        return $this->entityA;
    }

    public function setEntityA(EntityA $entityA)
    {
        $this->entityA = $entityA;
    }
}

// 表单类
class EntityType extends AbstractType
{
    public function buildForm(FormBuilderInterface $builder, array $options)
    {
        $builder
            ->add('entityBs', CollectionType::class, [
                'entry_type' => EntityBType::class,
                'allow_add' => true,
                'allow_delete' => true,
                'by_reference' => false,
            ]);
    }
}

// 控制器中的删除操作
public function deleteEntityBAction(EntityA $entityA, EntityB $entityB)
{
    $entityA->removeEntityB($entityB);
    $entityManager->remove($entityB);
    $entityManager->flush();

    // 其他操作...
}