Laravel hasManyThrough eloquent relationship tutorial example – onlinecode

In this tutorial, today we discuss about laravel hasManyThrough Eloquent relationship. Eloquent ORM means Object-relational Mapping and laravel provides a beautiful activerecord stucture. so we can easy to interact with application database. let’s start about hasManyThrough eloquent relationship.

Laravel hasManyThrough Eloquent relationship is woking with three tables of database. For example, The category is connected with products and products with orders, then we can access all orders connected with a specific category. categories have many products and products have many orders.

here, see below database stucture.

Categories

– id

– name

Products

– id

– category_id

– title

Orders

– id

– product_id

Setting Database Configuration

After complete installation of laravel. we have to database configuration. now we will open the .env file and change the database name, username, password in the .env file. See below changes in a .env file.

DB_CONNECTION=mysql
DB_HOST=127.0.0.1
DB_PORT=3306
DB_DATABASE=Enter_Your_Database_Name(has_many_through_relation)
DB_USERNAME=Enter_Your_Database_Username(root)
DB_PASSWORD=Enter_Your_Database_Password(root)

php artisan make:migration create_categories_table --create=categories
php artisan make:migration create_products_table --create=products
php artisan make:migration create_orders_table --create=orders

<?php
use IlluminateSupportFacadesSchema;
use IlluminateDatabaseSchemaBlueprint;
use IlluminateDatabaseMigrationsMigration;
class CreateCategoriesTable extends Migration
{
    /**
     * Run the migrations.
     *
     * @return void
     */
    public function up()
    {
        Schema::create('categories', function (Blueprint $table) {
            $table->bigIncrements('id');
            $table->string('name');
            $table->timestamps();
        });
    }
    /**
     * Reverse the migrations.
     *
     * @return void
     */
    public function down()
    {
        Schema::dropIfExists('categories');
    }
}
?>

<?php
use IlluminateSupportFacadesSchema;
use IlluminateDatabaseSchemaBlueprint;
use IlluminateDatabaseMigrationsMigration;
class CreateProductsTable extends Migration
{
    /**
     * Run the migrations.
     *
     * @return void
     */
    public function up()
    {
        Schema::create('products', function (Blueprint $table) {
            $table->bigIncrements('id');
	    $table->bigInteger('category_id')->unsigned();
            $table->foreign('category_id')->references('id')->on('categories')->onDelete('cascade');
            $table->string('title');
            $table->timestamps();
        });
    }
    /**
     * Reverse the migrations.
     *
     * @return void
     */
    public function down()
    {
        Schema::dropIfExists('products');
    }
}
?>

<?php
use IlluminateSupportFacadesSchema;
use IlluminateDatabaseSchemaBlueprint;
use IlluminateDatabaseMigrationsMigration;
class CreateOrdersTable extends Migration
{
    /**
     * Run the migrations.
     *
     * @return void
     */
    public function up()
    {
        Schema::create('orders', function (Blueprint $table) {
            $table->bigIncrements('id');
            $table->integer('product_id')->unsigned();
            $table->foreign('product_id')->references('id')->on('products')->onDelete('cascade');
            $table->timestamps();
        });
    }
    /**
     * Reverse the migrations.
     *
     * @return void
     */
    public function down()
    {
        Schema::dropIfExists('orders');
    }
}
?>

$post = file_get_contents('php://input');
$post = json_decode($post);
$sql = "INSERT INTO items (title) VALUES ('".$post->title."')";
$result = $mysqli->query($sql);

php artisan migrate

php artisan make:model Category
php artisan make:model Product
php artisan make:model Order

<?php
namespace App;
use IlluminateDatabaseEloquentModel;
class Category extends Model
{
    public function orders()
    {
        return $this->hasManyThrough(
            'AppOrder',
            'AppProduct',
            'category_id', // Foreign key on products table...
            'product_id', // Foreign key on orders table...
            'id', // Local key on categories table...
            'id' // Local key on products table...
        );
    }
}
?>

<?php
 
namespace App;
 
use IlluminateDatabaseEloquentModel;
 
class Product extends Model
{
    //
}

?>

<?php
 
namespace App;
 
use IlluminateDatabaseEloquentModel;
 
class Order extends Model
{
    //
}

?>

<?php
 
/*
|--------------------------------------------------------------------------
| Web Routes
|--------------------------------------------------------------------------
|
| Here is where you can register web routes for your application. These
| routes are loaded by the RouteServiceProvider within a group which
| contains the "web" middleware group. Now create something great!
|
*/
 
Route::get('/', function () {
    return view('welcome');
});
 
Route::get('product','productsController@index');

?>

php artisan make:controller ProductsController

<?php
namespace AppHttpControllers;
use AppOrder;
use AppCategory;
use IlluminateHttpRequest;
class ProductsController extends Controller
{
    /**
     * Display a listing of the resource.
     *
     * @return IlluminateHttpResponse
     */
    public function index()
    {
		$cate = Category::find(1);	
        $cateOrders = $cate->orders;
		//dd($cateOrders);
    }

}
?>