php - Call to undefined relationship [products] on model [AppCategory] in Laravel 7

Question

I am creating a simple inventory system using larvel 7. I ran in to the problem with

Call to undefined relationship [products] on model [AppCategory].

I am creating a two tables category and products I want have relationship with them.

Category table

id categoryname
1   drink
2   biscuits
3   toy

product table

id productname category
 1   fanta        1
 2   apple juice  1
 3    buildblocks 3 

I need to category table and product table look like this this and get the data and passing to the table. I need this below output:

id productname categoryname
1   fanta          drink 

While I am running the program I got this error:

Call to undefined relationship [products] on model [AppCategory].

I don't know why it has happing. What I tried so far I attached below.

Model

Category

    class Category extends Model
{
    
    protected $fillable = [
        'categoryname',
    ];


}

Product

class Product extends Model
{
    protected $fillable = [
        'product_name',
        'category',
    ];

    public function category (){
        return $this->belongsTo('AppModelsCategory','category','id');
    }
}

view.blade.php

 <tbody>
    @foreach ($products as $key => $product)
      <tr>
        <td>{{$key}}</td>
        <td>{{$product->product_name}}</td>
        <td>{{$product->category->categoryname}}</td>
      </tr>
    @endforeach
    </tbody>

Routes

Route::get('/products', 'ProductController@view')->name('product.view');

ProductController

<?php

namespace AppHttpControllers;
use AppProduct;
use AppCategory;

use IlluminateHttpRequest;

class ProductController extends Controller
{
    
    public function view()
    {
    $products = Product::with('category')->get();
    dd($products);
    $categories = Category::with('products')->get();
    return view ('product.view')-> with([
        'products' => $products,
        'categories' => $categories,
    ]);
    }

}

Answer 1

In your Category Model, you have to add the reverse relationship as well, because you are using it when you want to retrieve the list of the categories.

Category Model:

class Category extends Model
{
    protected $fillable = [
        'categoryname',
    ];

    public function products (){
        return $this->hasMany('AppModelsProduct','category','id');
    }
}

The above relationship declaration is important because you are referring to it in this line in your controller:

$categories = Category::with('products')->get();