> And what if I need to say that I can have two or three times the same
> topping on my pizza? Something like twice mozzarella cheese and 3
> times green olives topping?
>
> I though about an intermediary class and indeed this is the same
> solution found in those old posts mentioned before:
>
> class Topping(models.Model):
> # ...
>
> class ToppingAndQuantity(models.Model):
> amount = models.IntegerField()
> topping = models.ForeignKey(Topping)
>
> class Pizza(models.Model):
> # ...
> toppings = models.ManyToManyField(ToppingAndQuantity)
>
> I think it's ugly.
> Can you suggest me a better solution?
> It's that intermediary class really needed?
I believe this is the best way to do it. However, this generally
gets composed as
class Pizza(Model):
#don't reference toppings here
class ToppingAndQuantity(Model):
pizza = ForeignKey(Pizza)
topping = ForeignKey(Topping)
amount = PositiveIntegerField()
The information you want (the quantity) is associated with the
join between a pizza and its toppings. The ManyToMany would make
a situation where you could have one pizza that has both 2x
Cheese and 4x Cheese. I suspect that you want just one topping
per pizza, but a quantity associated with that one topping.
The ManyToMany is a nice shortcut for basically creating this
intermediate join model with only two FK fields in it (pizza and
topping) with a little syntactic sugar around them.
With the above, you should be able to do things somewhat like
p = Pizza.objects.get(id=1)
for topping in p.toppingandquantity_set:
print "%s x%i" % (p.topping, p.amount)
-tim
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