how to create relationship between three table in laravel? - laravel

Question

i have three table:
Suppliers
id | name | type
1 | Test1 | Seller
2 | Test2 | Manufacturer
Products
id | name
1 | product1
2 | product2
Prices
id | supplier_id | product_id | price
1 | 1 | 1 | 1000
2| 2 | 1 | 2000
each supplier have many products and each products belong to many suppliers.
Now each supplier can have a separate price for each product.
i have a question that how to create model and table for this scenario?

Answer 1

You will have two tables with models:
Product and Supplier
Within /Database/Migrations create_products table:
Schema::create('products', function (Blueprint $table) {
$table->id();
$table->string('name');
$table->timestamps();
});
create_suppliers table:
Schema::create('suppliers', function (Blueprint $table) {
$table->id();
$table->string('name');
$table->string('type');
$table->timestamps();
});
You will need a pivot table, so create it with Artisan command:
php artisan make:migration create_product_supplier_table
A quick note: Pivot names should be in alphabetical order to fit laravel name convention. 'P' letter comes first and then 'S' (product_supplier) in this case.
product_supplier table:
Schema::create('product_supplier', function (Blueprint $table) {
$table->id();
$table->unsignedBigInteger('product_id');
$table->unsignedBigInteger('supplier_id');
$table->integer('price');
$table->timestamps();
});
Now, you will need the following relation declarations in two models
Within App\Product class:
protected $guarded = [];
public function suppliers()
{
return $this->belongsToMany(Supplier::class)->withPivot('price');
}
And also in App\Supplier class:
protected $guarded = [];
public function products()
{
return $this->belongsToMany(Product::class)->withPivot('price');
}
You set it up now. Let's give it a try:
$supplier = App\Supplier::create(['name' => 'supplier1', 'type' => 'seller']);
$product = App\Product::create(['name' => 'product1']);
$supplier->products()->attach($product, ['price' => 80]);
Call it back:
$supplier->products; // it will give you the products that attached to supplier.
So, the any supplier can have any product with any price tag.