Doctrine manyToMany返回PersistentCollection而不是ArrayCollection

问题描述

我正在与Symfony 3.1和Doctrine 2.5一起工作。

我像往常一样设置一个manyToMany关系：

  manyToMany：
 placeServices：
 targetEntity：Acme\MyBundle\Entity\PlaceService 
 joinTable：
 name：place_place_service 
 joinColumns：
 place_id：
 referencedColumnName：id 
 inverseJoinColumns：
 place_service_id：
 referencedColumnName：id 
  / pre> 
 
 
并向我的实体添加方法
  protected $ placeServices ; 
 
 ... 
 
 public function __construct（）
 {
 $ this-> placeServices = new ArrayCollection（）; 
} 
 
 ... 
 
 / ** 
 * @return ArrayCollection 
 * / 
 public function getPlaceServices（） ：ArrayCollection 
 {
 return $ this-> placeServices; 
} 
 
 / ** 
 * @param PlaceServiceInterface $ placeService 
 * @return PlaceInterface 
 * / 
 public function addPlaceService（PlaceServiceInterface $ placeService）：PlaceInterface 
 {
 if（！$ this-> placeServices-> contains（$ placeService））{
 $ this-> placeServices-> add（$ placeService） ; 
} 
 
 return $ this; 
} 
 
 / ** 
 * @param PlaceServiceInterface $ placeService 
 * @return PlaceInterface 
 * / 
 public function removePlaceService（PlaceServiceInterface $ placeService）：PlaceInterface 
 {
 if（$ this-> placeServices-> contains（$ placeService））{
 $ this-> placeServices-> removeElement（$ placeService）; 
} 
 
 return $ this; 
} 
  
事情是，当我加载我的实体时，doctrine放一个 $ this-> placeServices属性中的PersistentCollection 。这不是一个大问题，除了当我建立一个表单来连接这两个实体（一个简单的复选框与symfony表单类型），当$ form-> handleRequest（）被触发时，Doctrine尝试注入新的数据在我的实体中，如果get / add / remove方法不使用 ArrayCollection ，则抛出错误。
 
 
 
我可以强制我的getter / add /删除将PersistentCollection转换为ArrayCollection（使用unwrap方法）的方法，但是所做的关系不会持久存在。
 
 
 
我找到了一个解决方法，如果我设置在属性使用ArrayCollection初始化的关系上，fetch =EAGER，并且关系被持久化。但我不知道这是一个很好的解决方案。
 
 
 
谢谢：）
解决方案> 
只需使用 Doctrine\Common\Collections\Collection 界面而不是ArrayCollection。  ArrayCollection 仅仅是集合的实现， PersistentCollection 。
 
 
 
 Doctine使用 PersistentCollection 用于延迟加载实体。你是对的，使用EAGER并不总是很好的解决方案，你可以有性能问题。
 
I'm working with Symfony 3.1 and Doctrine 2.5.
I setup a manyToMany relationship as I always do :
manyToMany:
        placeServices:
            targetEntity: Acme\MyBundle\Entity\PlaceService
            joinTable:
                name: place_place_service
                joinColumns:
                    place_id:
                        referencedColumnName: id
                inverseJoinColumns:
                    place_service_id:
                        referencedColumnName: id
And add methods to my Entity
    protected $placeServices;

    ...

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

    ...

    /**
     * @return ArrayCollection
     */
    public function getPlaceServices(): ArrayCollection
    {
        return $this->placeServices;
    }

    /**
     * @param PlaceServiceInterface $placeService
     * @return PlaceInterface
     */
    public function addPlaceService(PlaceServiceInterface $placeService): PlaceInterface
    {
        if(!$this->placeServices->contains($placeService)) {
            $this->placeServices->add($placeService);
        }

        return $this;
    }

    /**
     * @param PlaceServiceInterface $placeService
     * @return PlaceInterface
     */
    public function removePlaceService(PlaceServiceInterface $placeService): PlaceInterface
    {
        if($this->placeServices->contains($placeService)) {
            $this->placeServices->removeElement($placeService);
        }

        return $this;
    }
The thing is, when I load my entity, doctrine put a PersistentCollection in the $this->placeServices property. This does not sound like a big problem, except that when I build a form to connect those two entities (a simple multiple checkboxes with symfony form type), when $form->handleRequest() is triggered, Doctrine try to inject the new data in my entity, and throw an error if get/add/remove method are not using ArrayCollection.
I can force my getter/add/remove methods to transforme the PersistentCollection to ArrayCollection (using unwrap method) but then the relations made are not persisted.
I've found a workaround, if I set fetch="EAGER" on the relation the property is initialized with ArrayCollection, and the relation are persisted. But i'm not sure it's a good solution.
Thanks :)
 解决方案 
Just use Doctrine\Common\Collections\Collection interface instead of ArrayCollection. ArrayCollection is just a implementaton of Collection, as PersistentCollection.
Doctine uses PersistentCollection for lazy loading entities. You are right, using EAGER is not always good solution, you can have perfomance issues.
                        
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