CODE EXAMPLE FOR PYTHON

django Account has no customer

import email
from django.db import models
from django.db.models.fields.related import OneToOneField
from django.contrib.auth.models import User
from numpy import product 

# Create your models here.

class Customer(models.Model):
    user=models.OneToOneField(User, null=True, blank=True, on_delete=models.CASCADE)
    name = models.CharField(max_length=200, null=True)
    email=models.CharField(max_length=200)

    def __str__(self):
        return self.name

        

class Product(models.Model):
    name = models.CharField(max_length=200, null=True)
    price = models.FloatField()
    digital=models.BooleanField(default=False, null=True, blank=True)
    image = models.ImageField(null=True, blank=True)

    def __str__(self):
        return self.name
    #this is  to avoid erro in the template when we delete image
    @property
    def imageURL(self):
        try:
            url=self.image.url
        except:
            url=''
        return url


class Order(models.Model):
    customer=models.ForeignKey(Customer, on_delete=models.SET_NULL, null=True, blank=True)
    date_ordered=models.DateTimeField(auto_now_add=True)
    complete = models.BooleanField(default=False)
    transaction_id = models.CharField(max_length=200, null=True)

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

    @property
    def get_cart_total(self):
        orderitems = self.orderitem_set.all()
        total = sum([item.get_total for item in orderitems])
        return total

    @property
    def get_cart_items(self):
        orderitems = self.orderitem_set.all()
        total = sum([item.quantity for item in orderitems])
        return total

    


class OrderItem(models.Model):
    product=models.ForeignKey(Product, on_delete=models.SET_NULL, null=True, blank=True)
    order=models.ForeignKey(Order, on_delete=models.SET_NULL, null=True, blank=True)
    quantity = models.IntegerField(default=0, null=True, blank=True)
    date_added=models.DateTimeField(auto_now_add=True)

    @property
    def get_total(self):
        total = self.product.price * self.quantity
        return total


class ShippingAddress(models.Model):
    customer=models.ForeignKey(Customer, on_delete=models.SET_NULL, null=True, blank=True)
    order=models.ForeignKey(Order, on_delete=models.SET_NULL, null=True, blank=True)
    address= models.CharField(max_length=200, null=True)
    city = models.CharField(max_length=200, null=True)
    state = models.CharField(max_length=200, null=True)
    zipcode = models.CharField(max_length=200, null=True)
    date_added=models.DateTimeField(auto_now_add=True)

    def __str__(self):
        return self.address