Создание объекта для модели django

создана модель для заказов и модель для элементов заказа. когда мы создаем заказ через представление, почему 'user_id', когда имя поля в модели просто 'user'

models.py

class Order(models.Model):
user = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.CASCADE, related_name="order_user")

views.py

order = Order.objects.create(
        user_id=user_id,

Подобное произошло с orderitems

models.py

class OrderItem(models.Model):
    order = models.ForeignKey(Order, related_name="items", on_delete=models.CASCADE)

views.py

for item in basket:
        OrderItem.objects.create(order_id=order_id, product=item["product"], price=item["price"], quantity=item["qty"])

полный код order/models.py

from decimal import Decimal
from django.conf import settings
from django.db import models

from store.models import Product


class Order(models.Model):
    user = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.CASCADE, related_name="order_user")
    full_name = models.CharField(max_length=50)
    email = models.EmailField(max_length=254, blank=True)
    address1 = models.CharField(max_length=250)
    address2 = models.CharField(max_length=250)
    city = models.CharField(max_length=100)
    phone = models.CharField(max_length=100)
    postal_code = models.CharField(max_length=20)
    country_code = models.CharField(max_length=4, blank=True)
    created = models.DateTimeField(auto_now_add=True)
    updated = models.DateTimeField(auto_now=True)
    total_paid = models.DecimalField(max_digits=5, decimal_places=2)
    order_key = models.CharField(max_length=200)
    payment_option = models.CharField(max_length=200, blank=True)
    billing_status = models.BooleanField(default=False)

    class Meta:
        ordering = ("-created",)

    def __str__(self):
        return str(self.created)


class OrderItem(models.Model):
    order = models.ForeignKey(Order, related_name="items", on_delete=models.CASCADE)
    product = models.ForeignKey(Product, related_name="order_items", on_delete=models.CASCADE)
    price = models.DecimalField(max_digits=5, decimal_places=2)
    quantity = models.PositiveIntegerField(default=1)

    def __str__(self):
        return str(self.id)

checkout/views.py

def payment_complete(request):
    PPClient = PayPalClient()

    body = json.loads(request.body)
    data = body["orderID"]
    user_id = request.user.id

    requestorder = OrdersGetRequest(data)
    response = PPClient.client.execute(requestorder)

    total_paid = response.result.purchase_units[0].amount.value

    basket = Basket(request)
    order = Order.objects.create(
        user_id=user_id,
        full_name=response.result.purchase_units[0].shipping.name.full_name,
        email=response.result.payer.email_address,
        address1=response.result.purchase_units[0].shipping.address.address_line_1,
        address2=response.result.purchase_units[0].shipping.address.admin_area_2,
        postal_code=response.result.purchase_units[0].shipping.address.postal_code,
        country_code=response.result.purchase_units[0].shipping.address.country_code,
        total_paid=response.result.purchase_units[0].amount.value,
        order_key=response.result.id,
        payment_option="paypal",
        billing_status=True,
    )
    order_id = order.pk

    for item in basket:
        OrderItem.objects.create(order_id=order_id, product=item["product"], price=item["price"], quantity=item["qty"])

    return JsonResponse("Payment completed!", safe=False)

foo_field = foo_instance

foo_field_id = foo_id  #its primary key value, normally an integer.