Laravel, Simple and Correct way for relationship - laravel

Question

I want to list related categories of related brand with this logic.
Products Table
public function up()
{
Schema::create('products', function (Blueprint $table) {
$table->increments('id');
$table->string('name');
$table->string('slug');
$table->integer('brand_id')->unsigned();
$table->foreign('brand_id')->references('id')->on('brands')->onDelete('cascade');
$table->integer('category_id')->unsigned();
$table->foreign('category_id')->references('id')->on('categories')->onDelete('cascade');
$table->timestamps();
});
}
web.php
Route::get('{Brand}/{Category}/{Product}', 'ProductsController#show');
Route::get('{Brand}/{Category}', 'ProductsController#index');
1st route, for example; Samsung/phones should list all of Samsung's phones with following code part. Is there another way to make these codes simple? And this query returns null. I checked that query is getting correct columns but returns null.
use App\Product;
use App\Brand;
use App\Category;
class ProductsController extends Controller
{
public function index(Request $request)
{
$category = $request->Category;
$cat_id = Category::select('id')
->where('slug',$category)
->get();
$brand = $request->Brand;
$br_id = Brand::select('id')
->where('slug', $brand)
->get();
$products = Product::select('id','name','slug')
->where('category_id', $cat_id)
->where('brand_id', $br_id)
->get();
return view('products.index', compact('products'));
}
}
Product.php
class Product extends Model
{
public function brands()
{
return $this->belongsTo('App\Brand');
}
public function categories()
{
return $this->belongsTo('App\Category');
}
}
Category.php
class Category extends Model
{
public function brands()
{
return $this->belongsToMany('App\Brand');
}
public function products()
{
return $this->hasMany('App\Product');
}
}

Answer 1

First of all read the docs about laravel relationships:
https://laravel.com/docs/5.7/eloquent-relationships
The reason your current code is not working is because in your route you ask for parameters:
Route::get('{Brand}/{Category}', 'ProductsController#index');
But in your index() method on your ProductsController you have not included these parameters.
public function index(Request $request, Brand $brand, Category $category)
The second problem in your code is that you are not using your relationships at all. Your current controller just makes a new eloquent query.
Example of getting all the products for the given category using the method you have defined on your Category Model:
public function index(Request $request, Brand $brand, Category $category)
{
$products = $category->products;
return view('products.index', compact('products'));
}
Example of extending this with the given brand:
public function index(Request $request, Brand $brand, Category $category)
{
$products = $category->products()->where('brand_id', $brand->id)->get();
return view('products.index', compact('products'));
}
UPDATE
As noted in the comments, the URL parameters are slugs and not ids, so auto route-model-binding will not work. An updated solution with slugs:
public function index(Request $request, $brand, $category)
{
$categoryModel = Category::where('slug', $category)->firstOrFail();
$brandModel = Brand::where('slug', $brand)->firstOrFail();
$products = $categoryModel->products()->where('brand_id', $brandModel->id)->get();
return view('products.index', compact('products'));
}
Further improving your code would be to add a scope or helper method so you can do something like Brand::FindBySlug($slug);

Answer 2

I think you are using get method at last that will give you array not only one value. Could you please try with below code. This might help
use App\Product;
use App\Brand;
use App\Category;
class ProductsController extends Controller
{
public function index(Request $request)
{
$category = $request->Category;
$cat_id = Category::where('slug',$category)->value('id);
$brand = $request->Brand;
$br_id = Brand::where('slug', $brand)->value('id);
$products = Product::select('id','name','slug')
->where('category_id', $cat_id)
->where('brand_id', $br_id)
->get();
return view('products.index', compact('products'));
}
}

Answer 3

You should try this:
public function index($brand, $category,Request $request)
{
$products = Product::select('id','name','slug')
->where('category_id', $category)
->where('brand_id', $brand)
->get();
return view('products.index', compact('products'));
}