django query with Q and multiple categories

Question

I ve got the following model structure:

class Pizza(models.Model):
    name = models.CharField(max_length=50)
    shop = models.CharField(max_length=50)


class Topping(models.Model):
    name = models.CharField(max_length=50)
    pizza = models.ManyToManyField(Pizza)

I want to find all pizzas which are with ham or cheese or both, is this the standard django way?: from django.db.models import Q

Pizza.objects.filter(Q(topping__name='ham') | Q(topping__name='cheese'))

How do i do it programatically, if i got a list of toppings, eg?:

['ham','cheese']

Answer 1

You could do it with dicts and **kwargs, but there's no need: easier to just use __in :

topping_list = ['ham', 'cheese']
Pizza.objects.filter(topping__name__in=topping_list)

Answer 2

I would definitely swap the manytomany relationship to point from Pizza to Topping. Why would you query all toppings objects first to get the list then compare it against the Pizza? I believe you mostly want to show a pizza with their toppings and not showing a list of pizzas that have a particular topping. Would make it easier I guess (unless your app is mostly about the topping)...