Model access in Laravel > 5 - php

Question

First of all, I'm new to Laravel. I come from Codeigniter where you can have something similar to:
class Test_Model extends CI_Model {
public function test_method($a, $b){
return $a * $b;
}
}
class Test_Controller extends CI_Controller {
public function __construct(){
$this->load->model('Test');
}
public function method1() {
$z = $this->Test->test_method(3,4);
}
}
As you can see, the model was loaded and all it's methods were available. In my opinion it's pretty straightforward.
Now, I've got the following in Laravel:
namespace App;
use Illuminate\Database\Eloquent\Model;
// Order Model
class Order extends Model
{
protected $fillable = ['user_id'];
public function orderItems()
{
return $this->hasMany(orderItem::class);
}
}
// orderItem model
namespace App;
use Illuminate\Database\Eloquent\Model;
class orderItem extends Model
{
protected $fillable = [
'order_id',
'item_id',
'type',
'quantity',
'price',
'subtotal'
];
public function order()
{
return $this->belongsTo(Order::class);
}
}
// Orders Controller
namespace App\Http\Controllers;
use Illuminate\Http\Request;
use App\Order;
use App\orderItem;
class OrdersController extends Controller
{
private $orderId;
public function store(Request $request)
{
// check if there's already a cart [order] for this user, if not create one
$this->orderId = Order::where('user_id', $request->json('user_id'))->get(['id']);
$item = [
'item_id' => $request->json('item_id'),
'type' => $request->json('type'),
'quantity' => $request->json('quantity'),
'price' => $request->json('price'),
];
if (!$this->orderId->count()){
$this->orderId = Order::insertGetId([
'user_id' => $request->json('user_id')
]);
}
$orderItem = new Order();
$orderItem->addOrderItem($item, $this->orderId);
}
}
Two questions I've got:
Is there a simpler or cleaner (not saying that creating a new obj is not clean) to access the Order model methods (such as done in Codeigniter)?
I've learnt a little bit about how to establish relationships between models in Laravel. I've got two other tables name Record and Artist respectively (a 1 to many relationship) and I can do the following:
$record = Record::findOrFail($id);
$record['artist_name'] = $record->artist->name;
but when I try to do the same with the Order and orderItem (also a 1 to many relationship) it doesn't work:
$cart = Order::where('user_id', $user->id)->get();
// Retrieve existing items in cart
$cart_items = $cart->orderItems();
Why is that?

Answer 1

As for question 1:
If the method has nothing to do with the actual instance of the model I would strongly recommend not putting it on the model. You could create a separate class that doesn't extend Model class as there is no need to.
If you really want to, you could create a static method though.
If it does depend on the model (database row), there's no way of not instantiating it as it will need to know which database row to work on.
As for question 2:
This part $cart_items = $cart->orderItems(); only returns a query builder (as you're calling it as a function and not a property). Which lets you chain other query builder methods off of it.
For example $cart_items = $cart->orderItems()->get(); will return the actual order items.
Or you could just call it as a property and get the same result:
$cart_items = $cart->orderItems;
While the above should work, it is generally suggested that you eager load the relationships (especially when you're pulling multiple rows of the parent model), which would look like this (the ->with() part will eager load them):
$cart = Order::where('user_id', $user->id)->with('orderItems')->get();
$cart_items = $cart->orderItems;