Laravel 4 热切加载“未定义的属性”
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原文地址: http://stackoverflow.com/questions/17748655/
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Laravel 4 Eager Loading "Undefined Property"
提问by Jared Meyering
Why can't I access the property in an eager loaded senario?
为什么我不能在急切加载的场景中访问该属性？
I am trying to access the photo location for my facilities model. They have a Many:Many relationship. When I load the facility info using
我正在尝试访问我的设施模型的照片位置。他们有一个多：多的关系。当我使用加载设施信息时
$facilities = Facility::with('photos')->get();
When I try to access
当我尝试访问时
foreach($facilities as $facility)
{
echo $facility->photos->id;
}
I get the Undefined property: Illuminate\Database\Eloquent\Collection::$id
我得到 Undefined property: Illuminate\Database\Eloquent\Collection::$id
If I echo $facilities->photosI end up with.
如果我回应$facilities->photos我最终。
[{"id":"3",
"name":null,
"location":"facilities\/facility1.jpg\r",
"created_at":"2013-07-18 14:15:19",
"deleted_at":null,
"updated_at":null,
"pivot":{"facility_id":"5","photo_id":"3"}}]
Whats the best way to access any property in this array?
访问此数组中任何属性的最佳方法是什么？
回答by Altrim
With eager loading the photosyou get a photoscollection and in order to get the photo you need to iterate through the photoscollection e.g.
随着急切加载，photos你会得到一个photos集合，为了得到照片，你需要遍历photos集合，例如
foreach($facilities as $facility)
{
foreach($facility->photos as $photo)
{
echo $photo->id;
}
}
If you only want just the first photo you can get it by calling the first()method on the collection
如果你只想要第一张照片，你可以通过调用first()集合上的方法来获取它
foreach($facilities as $facility)
{
$facility->photos->first()->id;
}
回答by sidneydobber
What is received from the database is an array with one object. This is why a foreach works. To access it the way you want you should add the first() method just as Atrim says, you can even drop the get() method. Only I would suggest doing it in the controller.
从数据库接收到的是一个包含一个对象的数组。这就是 foreach 起作用的原因。要以您想要的方式访问它，您应该像 Atrim 所说的那样添加 first() 方法，您甚至可以删除 get() 方法。只有我会建议在控制器中进行。
$facilities = Facility::with('photos')->first();
{{ $facilities->location }}
回答by AZReed
Thanks Altim, I just hit this problem too and the nested foreach is one of the solutions. Nevertheless, I'll share with you guys the solution that I used at the end.
谢谢 Altim，我也遇到了这个问题，嵌套的 foreach 是解决方案之一。尽管如此，我还是会与大家分享我最后使用的解决方案。
Instead of the nested foreach or even the eager loader, I used a Join Query Builder. In my case:
我使用了 Join Query Builder，而不是嵌套的 foreach 甚至是eager loader。就我而言：
$posts = DB::table('posts')
->leftJoin('users', 'posts.user_id', '=', 'users.id')
->get();
This allowed me to use one foreach, and all the data is at the same level, in my case for instance would be something like:
这使我可以使用一个 foreach，并且所有数据都处于同一级别，例如在我的情况下将是这样的：
@foreach ($posts as $post)
<p>{{ $post->first_name }}</p> # From users table
<p>{{ $post->title }}</p> # From posts table
<p>{{ $post->body }}</p>
@endforeach
Maybe it is not answering this question exactly , but hope it helps to others like me that ended up in this particular question.
也许它并没有完全回答这个问题，但希望它对像我这样最终解决这个特定问题的其他人有所帮助。
