使用 Laravel Eloquent 需要根据类别 id 获取所有产品

Question

I need to get all products according to its category id. This is my controller.

UserProductsController

class UserProductsController extends Controller
{
    public function index()
    {
        $products = Product::get();
        return view ('products')->with(compact('products'));
      
    }
      
    public function product_categories()
    {
        $categories = Category::all();
        return view ('categories')->with(compact('categories'));
      
    }


    public function products(Category $category)
    {
        $category->load('products');

        return view('categorize')->withCategory($category);
    } 
  

}

This is my blade file.

    @foreach($category as $c) 
     <div class="mb-2" class="font-size-12 text-gray-5">{{ $c ['cat_name'] }}</a></div>
        <h5 class="mb-1 product-item__title" class="text-blue font-weight-bold">{{ $c ['prod_name'] }}</a></h5>
            <li class="line-clamp-1 mb-1 list-bullet">{{ $c ['prod_description'] }}</li>
            <div class="text-gray-20 mb-2 font-size-12">{{ $c ['prod_item_code'] }}</div>
            <div class="flex-center-between mb-1">
                <div class="prodcut-price">
                   <div class="text-gray-100">LKR {{ $c ['prod_price'] }}.00</div>
                </div>
            </div>
        </div>
@endforeach

This is my route file.

Route::get('/categorize/{category_id}', 'UserProductsController@products')->name('categorize');

This is the Categories table.

public function up()
    {
       Schema::create('categories', function (Blueprint $table)
        {
        $table->bigIncrements('id');
        $table->unsignedBigInteger('parent_id')->nullable();
        $table->string('cat_name')->nullable();
        $table->string('cat_image_path')->nullable();
        $table->timestamps();
         });
    }

This is my Products table.

public function up()
    {
        Schema::create('products', function (Blueprint $table) {
            $table->bigIncrements('id');
            $table->string('prod_name');
            $table->string('prod_brand')->nullable();
            $table->unsignedBigInteger('category_id');
            $table->string('prod_description')->nullable();
            $table->string('prod_item_code')->nullable();
            $table->string('prod_modal')->nullable();
            $table->string('prod_size')->nullable();
            $table->string('prod_weight')->nullable();
            $table->string('prod_height')->nullable();
            $table->string('prod_manufacturer')->nullable();
            $table->float('prod_price')->nullable();
            $table->float('prod_discount')->nullable();
            $table->float('prod_quantity')->nullable();
            $table->string('prod_image_path')->nullable();
            $table->timestamps();

            $table->foreign('category_id')
            ->references('id')
            ->on('categories')
            ->onDelete('cascade');
        });
    }

This is my category model.

<?php

namespace App;

use Illuminate\Database\Eloquent\Model;


class Category extends Model
{
    public function products()
    {
       return $this->hasMany(Product::class);
    }
}

This is my product model.

<?php

namespace App;

use Illuminate\Database\Eloquent\Model;
use Storage;

class Product extends Model
{
    public function category()
    {
        return $this->belongsTo('App\Category');
    }
}

When I select the particular category my URL is directing me to that category_id's page, but the data doesn't pass. What could be the problem? Anyone please direct me?

Answer 1

You can do that with eager loading. Eager loading is a concept in which when retrieving items, you get all the needed items together with all (or most) related items at the same time. This is in contrast to lazy loading where you only get one item at one go and then retrieve related items only when needed

Category model :

public function products()
{
   return $this->hasMany(Product::class);
}

On your controller :

public function products(Request $request, $category_id)
{
    $category= Category::with('products')->findOrFail($category_id);
    return view('categorize')->with(compact('category'));
}

Answer 2

what I understand, is that you have some 'category id' in frontend( maybe HTML) and you want to pass that id via some route '/categorize/{category_id}' to your controller and get the all products associate with it. so you have to refactor your controller method like below.

 public function products(int $category_id)
{
     $products = Product::where('category_id',$category_id)->get();
    return view ('categorize')->with(compact('products'));
} 

If you have any different needs then feel free to ask and elaborate more about your problem. I will definitely help you.

Answer 3

as u mention category_id in your route so in controller u need to do

 public function products(Category $category_id) // parameter name should match with router param
    {
        $category_id->load('products');
        $category  = $categoryid;
        return view('categorize')->withCategory($category);
    } 

Or correct way u can do this

Route::get('/categorize/{category}', 'UserProductsController@products')->name('categorize');

category_id to category then your route model binding will work

ref link https://laravel.com/docs/7.x/routing#route-model-binding

Answer 4

If you want to use route model binding, you'll have to define your route like so:

Route::get('/categorize/{category}', 'UserProductsController@products')->name('categorize');

So in this case $category is actually a model, not a collection. So the foreach you currently have doesn't make sense. It should be something like:

@foreach($category->products as $product) 
    <div>{{ $product->prod_name }}</div>
    ...
@endforeach