Retrieving relationships of relationships using Eloquent - laravel

Question

I have a database with the following tables and relationships:
invoice ,order & product
each factor has several orders,and every orders point to a product.
Invoice Model:
class Invoice extends Model
{
public function orders()
{
return $this->hasMany(Order::class);
}
}
Order Model:
class order extends Model
{
public function invoice()
{
return $this->belongsTo(Invoice::class);
}
public function product()
{
return $this->belongsTo('App\Product');
}
}
Product Model:
class product extends Model
{
public function orders()
{
return $this->belongsToMany(Order::class);
}
}
the name of each order is foreign key to the product id,
$table->unsignedBigInteger('name')->references('id')->on('products')->default(0);
in my template i can showing the invoice with orders like this:
{{$invoice->title}}
{{$invoice->client_address}}
#foreach($invoice->orders as $order)
{{$order->name}}
${{$order->price}}
{{$order->qty}}
${{$order->qty * $order->price}}
#endforeach
with this function:
public function show($id)
{
$invoice = Invoice::with('orders')->findOrFail($id);
return view('admin.invoice.show.main', compact('invoice'));
}
how can show the name of product in orders recorde like this:
{{$order->product->name}}
im using before for single loop(e.g., product & category)
but in this example we have 3 relation and using a compact method before.
My product table is:
Schema::create('products', function (Blueprint $table) {
$table->bigIncrements('id');
$table->string('name');
$table->string('desc');
$table->string('price');
$table->string('image');
$table->string('count');
$table->string('status');
$table->unsignedBigInteger('category_id')->default(0);
$table->foreign('category_id')->references('id')->on('categories');
$table->timestamps();
});

Answer 1

Try this
$invoice = Invoice::with('orders.product')->findOrFail($id);
You can access using something like that
#foreach($invoice->orders as $order)
..
{{ $order->product->name }}
..
#endforeach

Answer 2

I think your relations is wrong...Each product can be within a few orders..so:
Product Model:
class product extends Model
{
public function orders()
{
return $this->belongsToMany('App\Order');
}
}
Order Model:
class order extends Model
{
public function product()
{
return $this->hasOne('App\Product');
}
}
right?
Then access with:
$invoices = Invoice::with('orders.product')->get();