decided to make API on DRF in his free time. For learning purposes.
API will be similar from the online menu.
When creating models, a question appeared how to properly calculate the total number of identical products. Test one client can admit can buy 5 burgers, and when adding them to the basket, I want to implement the product name + number + total price.
If you know suitable literature, also a good option.
(not common on the database, but by aggregating in Django ORM)
For greater understanding, current models look like this:

from django.db import models
from django.contrib.auth import get_user_model
User = get_user_model
Class Category:
  Name = Models.charfield ('name category', max_length = 200, unique = true)
  Slug = Models.Slugfield ()
  Description = Models.TextField ('Description category')
  Class Meta:
    Ordering = ['Name']
  DEF __STR __ (SELF):
    Return Self.name.
Class Product:
  Name = Models.charfield ('product name', max_length = 100, unique = true)
  Description = Models.TextField ('Product Description', Blank = True, NULL = TRUE)
  Category = Models.ForeignKey (
    Category,
    ON_DELETE = MODELS.SET_NULL,
    related_name = 'Category'
  )
  Price = Models.decimalfield (decimal_places = 2)
  Class Meta:
    Ordering = ['Name']
  DEF __STR __ (SELF):
    Return Self.name.
Class Basket (Models.Model):
  User = Models.ForeignKey (
    User, On_delete = Models.Cascade, Related_Name = 'Allbasket'
  )
  Products = Models.ForeignKey (
    Product, On_delete = Models.cascade, Related_Name = 'Alluser'
  )
  Created = Models.dateTimeField (AUTO_NOW_ADD = TRUE)
  DEF __STR __ (SELF):
    Return F '{Self.user} {self.products}'

Thank you in advance!

Answer 1

You can create Property method>Basket Basket for counting the consoles of goods in the basket:

class basket (models.model):
...
  @Property.
  DEF Get_Quantity ():
    Return Self.Products.all (). Count ()

You can call this method like this:

basket = basket.objects.all ()
For Item in Basket:
  item.get_quantity ()