Doctrine2 ArrayCollection [英] Doctrine2 ArrayCollection

问题描述

好的，我有一个用户实体如下

Ok, I have a User entity as follows

<?php
class User 
{
    /**
     * @var integer
     * @Id
     * @Column(type="integer")
     * @GeneratedValue
     */
    protected $id;
    /**
     * @var \Application\Entity\Url[]
     * @OneToMany(targetEntity="Url", mappedBy="user", cascade={"persist", "remove"})
     */
    protected $urls;
    public function __construct()
    {
        $this->urls = new \Doctrine\Common\Collections\ArrayCollection();
    }
    public function addUrl($url)
    {
       // This is where I have a problem
    }
}

现在，我想做的是检查用户是否已经有 $ url $ urls ArrayCollection 之前$ c $ $ $ url 。

Now, what I want to do is check if the User has already the $url in the $urls ArrayCollection before persisting the $url.

现在我发现的一些例子说明我们应该做些类似于

Now some of the examples I found says we should do something like

if (!$this->getUrls()->contains($url)) {
    // add url
}

但这不起作用，因为这比较了元素值。由于 $ url 还没有 id 的价值，这将永远失败， $ url 将被公开。

but this doesn't work as this compares the element values. As the $url doesn't have id value yet, this will always fail and $url will be dublicated.

所以我真的很感激，如果有人可以解释如何添加一个元素到ArrayCollection 没有

So I'd really appreciate if someone could explain how I can add an element to the ArrayCollection without persisting it and avoiding the duplication?

修改

我已经设法通过

$p = function ($key, $element) use ($url) 
{ 
    if ($element->getUrlHash() == $url->getUrlHash()) { 
        return true; 
    } else { 
        return false; 
    } 
};

但是这个还没有加载所有的URL，然后执行检查？我不认为这是有效的，因为每个用户可能有数千个URL。

But doesn't this still load all urls and then performs the check? I don't think this is efficient as there might be thousands of urls per user.

推荐答案

这是不可能的域驱动的方式，即只是使用对象。您应该执行一个查询来检查存在：

This is not yet possible in a "domain driven" way, ie. just using objects. You should execute a query to check for the existance:

SELECT count（u.id）FROM User u WHERE？1 IN u.urls AND u.id =？2

SELECT count(u.id) FROM User u WHERE ?1 IN u.urls AND u.id = ?2

使用Doctrine 2.1可以使用两个新功能的组合：

With Doctrine 2.1 this will be possible using a combination of two new features:

1. 额外的懒惰集合


2. @IndexBy用于集合，因此您可以定义@OneToMany（targetEntity =Url，indexBy =location）


3. ExtraLazy Collection通过使用 - > contains（）来支持索引。

点1和2已经在Doctrine 2主程序中实现，但3仍然缺少。

Points 1 and 2 are already implemented in Doctrine 2 master, but 3 is still missing.

这篇关于Doctrine2 ArrayCollection的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！