doctrine2 删除多对多关系

发布于 2024-09-18 11:29:44 字数 649 浏览 2 评论 0原文

我有一个具有以下类成员和映射的组实体：

/**
 * @ManyToMany(targetEntity="Group", cascade={"persist"})
 * @JoinTable(name="groups_children",
 *      joinColumns={@JoinColumn(name="group_id", referencedColumnName="id")},
 *      inverseJoinColumns={@JoinColumn(name="child_id", referencedColumnName="id", unique=true)}
 *      )
 */
private $children;

添加子项很简单：

public function addChild(Group $group)
{
    if (! $this->hasChild($group)) {
        $this->children[] = $group;
        App::getEntityManager()->persist($this);
    }
}

删除子项：

???????

如何删除子项？

原文

I have a Group Entity with the following class member and mapping:

/**
 * @ManyToMany(targetEntity="Group", cascade={"persist"})
 * @JoinTable(name="groups_children",
 *      joinColumns={@JoinColumn(name="group_id", referencedColumnName="id")},
 *      inverseJoinColumns={@JoinColumn(name="child_id", referencedColumnName="id", unique=true)}
 *      )
 */
private $children;

Adding a child is trivial:

public function addChild(Group $group)
{
    if (! $this->hasChild($group)) {
        $this->children[] = $group;
        App::getEntityManager()->persist($this);
    }
}

Removing a child:

???????

How would I remove a child?

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荆棘i 2024-09-25 11:29:44

当 Doctrine 从关系中检索值列表时，它使用 ArrayCollection< 的实例/a> 与常规数组相反。

ArrayCollection 实现了 ArrayAccess，这意味着 unset 可以正常工作。

然而，一种更简单的方法是：

   $this->getChildren()->removeElement($child) // to remove by object
   $this->getChildren()->remove($index) // to remove by array index

尽管，我对您当前的示例有点困惑。为什么假设连接表中的子 ID 和组 ID 应该相同？为什么在添加示例中将 $group 添加到 $children[] 数组中？无意批评，但这会让解析你的意图变得困难。

When Doctrine retrieves a list of values from a relationship, it uses an instance of ArrayCollection as opposed to a regular array.

ArrayCollection implements ArrayAccess, which means that unset works just fine.

However, an simpler way of doing it would be:

   $this->getChildren()->removeElement($child) // to remove by object
   $this->getChildren()->remove($index) // to remove by array index

Although, I'm a little confused with your current example. Why are you assuming that the Child id and Group id should be identical in the join table? And why in your adding example are you adding $group to the $children[] array? Don't mean to be critical, but it makes parsing your intention difficult.

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朮生 2024-09-25 11:29:44

public function removeChild(Group $group)
{
    foreach ($this->getChildren() as $key => $child)
    {
        if ($child->getId() == $group->getId())
            unset($this->children[$key]);
            break;
    }
}

这有效。但这是最有效的方法吗？

public function removeChild(Group $group)
{
    foreach ($this->getChildren() as $key => $child)
    {
        if ($child->getId() == $group->getId())
            unset($this->children[$key]);
            break;
    }
}

This works. Is it the most efficient way though?

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