Django Particular wise total in their respective rows - django

Question

I am trying to print a particular wise total in the invoice using Django. The problem is if I use for loop, it prints the last items particular wise total in everywhere. I am confused what will be the best way to calculate individual total in their respective rows?
Here is my Views.py:
def order_complete(request):
order_number = request.GET.get('order_number')
transID = request.GET.get('payment_id')
try:
order = Order.objects.get(order_number=order_number, is_ordered=True)
ordered_products = OrderProduct.objects.filter(order_id = order.id)
total=0
subtotal = 0
for i in ordered_products:
total = i.product_price * i.quantity
subtotal += total
payment = Payment.objects.get(payment_id = transID)
context ={
'order': order,
'ordered_products': ordered_products,
'order_number': order.order_number,
'transID': payment.payment_id,
'payment': payment,
'subtotal': subtotal,
'total':total,
}
return render(request, 'orders/order_complete.html', context)
except(Payment.DoesNotExist, Order.DoesNotExist):
return redirect('home')
models.py
class OrderProduct(models.Model):
order = models.ForeignKey(Order, on_delete=models.CASCADE)
payment = models.ForeignKey(Payment, on_delete=models.SET_NULL, blank=True, null=True)
user = models.ForeignKey(Account, on_delete=models.CASCADE)
product = models.ForeignKey(Product, on_delete=models.CASCADE)
variations = models.ManyToManyField(Variation, blank=True)
quantity = models.IntegerField()
product_price = models.FloatField()
ordered = models.BooleanField(default=False)
created_at = models.DateTimeField(auto_now_add=True)
updated_at = models.DateTimeField(auto_now_add=True)
def __str__(self):
return self.product.product_name
template
<dd class="text-right">${{ total }}</dd>
suggestion/solutions would be highly appreciated.
Here is the result

Answer 1

My suggestion is to always store total_amount in the table itself along with unit_price and quantity,
Cause this way, if you ever want to get the item's unit cost you can simply access it on order table itself and total to tell that this is the total of unit price x quantity
1 more advantage you get by this i.e. when calculating the final total of all order items you can simply write the following to get it
from django.db.models import Sum
order_products = OrderProduct.objects.filter(order_id=order.id)
total_amount = order_products.aggregate(Sum('total_amount'))["total_amount__sum"]
# total_amount is the new field to add in OrderProduct table which stores
# quantity * unit_price at the time of creation
This way, you will directly get individual total & sum of those totals