Django models deifinition many to many field

Question

I have the following case:

class Product(models.Model):
    name = models.CharField(max_length=200)

class Order(models.Model):
    product = models.ManyToManyField(Product)
    quantity = models.IntegerField(default=0,validators=[MinValueValidator(1)])

and in admin.py

class ProductsInline(admin.TabularInline):
    model = Order.product.through

class OrderAdmin(admin.ModelAdmin):
    inlines = [ProductsInline,]
    filter_horizontal = ('product',)

I would like to enter a different quantity for each product while creating one order but with this models it is not possible. Only one quantity per order can be inserted.

I thought of creating an intermediate class ProductQuantity that has a product and its quantity, and then add this to an Order, but i don't know if it is possible to create a ProductQuantity "on the fly" when creating an order.

I can't think of any solution, can anyone help?

Answer 1

I am not sure if I get your questions. Would this solve your problem?

class Product(models.Model):
    name = models.CharField(max_length=200)

class Order(models.Model):
    customer = models.ForeignKey(Customer)

class OrderItem(models.Model):
    order = models.ForeignKey(Order)
    product = models.ManyToManyField(ProductQuantity)
    quantity = models.IntegerField(default=0,validators=[MinValueValidator(1)])

Edit:

With the above Model you could create the following Orders:

Products:
+----+--------+
| id |  name  |
+----+--------+
|  1 | apple  |
|  2 | orange |
|  3 | banana |
+----+--------+

Order:
+----+-------------+
| id | customer_id |
+----+-------------+
|  1 |         112 |
|  2 |          99 |
+----+-------------+

OrderItem:
+----+-------+---------+----------+
| id | order | product | quantity |
+----+-------+---------+----------+
|  1 |     1 |       1 |       10 |
|  2 |     1 |       2 |       20 |
|  3 |     1 |       3 |       30 |
|  4 |     2 |       1 |        5 |
+----+-------+---------+----------+

There are two orders from two different customers, one with 10 apples, 20 oranges and 30 bananas. And a second order with only one item of 5 apples.