Updating Cart in Django Admin on Adding and Removing Items

Question

I have the following models in my application in which I add items to a cart and can remove them too. The adding and removing of a cart item has been achieved through my views but what i want is that about how can I do this in Admin.

class Product(models.Model):
    product_name=models.CharField(max_length=32)
    price=models.IntegerField()

class Cart(models.Model):
    cust_id=models.ForeignKey(User, on_delete=models.CASCADE)
    count=models.IntegerField(default=0)
    total=models.IntegerField(default=0)

class Cart_Item(models.Model):
    item=models.ForeignKey(Product, blank=True, null=True, on_delete=models.CASCADE)
    quantity=models.IntegerField()
    cart=models.ForeignKey(Cart, on_delete=models.CASCADE)

What I want to achieve in Admin is that that if I add or remove a Cart_Item object in Admin, it should update the corresponding values of count and total in Cart accordingly for that particular user

Accepted Answer

I would consider count and total to be model methods of Cart, like this:

Must Read

Solution 1


from django.db.models import Sum

class Product(models.Model):
    product_name=models.CharField(max_length=32)
    price=models.IntegerField()

class Cart(models.Model):
    cust_id=models.ForeignKey(User, on_delete=models.CASCADE)
    # Model Property
    @property
    def count(self):
        return Cart_Item.objects.filter(cart=self).count()
    @property
    def total(self):
        return Cart_Item.objects.filter(cart=self).item.aggregate(Sum('price'))
class Cart_Item(models.Model):
    item=models.ForeignKey(Product, blank=True, null=True, on_delete=models.CASCADE)
    quantity=models.IntegerField()
    cart=models.ForeignKey(Cart, on_delete=models.CASCADE)

You can then access the count and total just like you would access any other field, like this:

cart = Cart(cust_id=user)
items_in_cart = cart.items
total_balance = cart.amount

Updating Cart in Django Admin on Adding and Removing Items

1 Answer

Must Read

Solution 1

Marcus Vance