在 laravel 5.4 中发现错误，此集合实例上不存在属性 [categories]
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found error in laravel 5.4,Property [categories] does not exist on this collection instance
提问by vaibhav
I am trying to display the product listing on listing page of the product. Each product has category.My table structure
我正在尝试在产品的列表页面上显示产品列表。每个产品都有类别。我的表结构
categories
id name description
1 Cat1 Category 1
2 Cat2 Category 2
This is the category table having id name and description
这是类别表 id name and description
products
id name description category_id
1 pro1 product 1 1
2 pro2 product 2 2
This is the product table having category_id.
这是具有 category_id 的产品表。
Product Model
public function categories() {
return $this->belongsTo("App\Category");
}
This is the product model where the products are belongs to category
这是产品所属类别的产品型号
Category Model
public function products() {
return $this->hasMany("App\Product");
}
This is the Category model where the Category has many product
这是Category 有很多产品的Category 模型
Now in the product controller on listing function I want the list of product with category name
现在在列表功能的产品控制器中，我想要带有类别名称的产品列表
public function index()
{
$product = Product::with('categories')->get();
print_r($product->categories);die;
return view('product.index')->with("list",$product);
}
I want my Output should be
我希望我的输出应该是
products
id name description category name
1 pro1 product 1 cat1
2 pro2 product 2 cat2
I found this error "Property [categories] does not exist on this collection instance."
我发现了这个错误 "Property [categories] does not exist on this collection instance."
回答by Marcin Nabia?ek
When you run:
当你运行时：
$product = Product::with('categories')->get();
you are not getting single products but all products so it should be rather renamed to:
您得到的不是单一产品，而是所有产品，因此应该将其重命名为：
$products = Product::with('categories')->get();
Further, looking at your database structure, each product belongs to single category so in Productmodel you should rename
此外，查看您的数据库结构，每个产品都属于单个类别，因此在Product模型中您应该重命名
public function categories()
{
return $this->belongsTo("App\Category");
}
to
到
public function category()
{
return $this->belongsTo("App\Category");
}
If you do this change, you should then again change
如果您进行此更改，则应该再次更改
$products = Product::with('categories')->get();
to
到
$products = Product::with('category')->get();
Going back to your controller assuming all your products have set category, you can display it like this:
回到你的控制器，假设你的所有产品都设置了类别，你可以这样显示：
foreach ($products as $product)
{
echo $product->id.' '.$product->name.' '.$product->description.' '.$product->category->name;
}
You can obviously do the same later in Blade view like so:
你显然可以稍后在 Blade 视图中执行相同的操作，如下所示：
@foreach ($list as $product)
{{ $product->id }} {{$product->name}} {{ $product->description }} {{ $product->category->name }}
@endforeach
回答by vaibhav
I have changed in ProductControllerwhich is my product controllers function
我改变了ProductController我的产品控制器功能
public function index()
{
$products = Product::with('category')->get();
return view('product.index')->with("list",$products);
}
Also changed in Product Model
产品型号也发生了变化
public function category() {
return $this->belongsTo("App\Category");
}
After these changes I got my expected result.
经过这些更改后，我得到了预期的结果。
