In Django, if I have a ManyToManyField:
class Topping(models.Model):
name = models.CharField(max_length=30)
class Pizza(models.Model):
name = models.CharField(max_length=50)
toppings = models.ManyToManyField(Topping)
I can minimize hits on the database when accessing the Pizza
model's toppings
field by using prefetch_related() :
Pizza.objects.all().prefetch_related('toppings')
How can I do the same but in reverse, to prefetch the pizza_set
from a Topping
queryset?
This doesn't work, and I couldn't find it in the docs:
Topping.objects.all().prefetch_related('pizza_set')
This should work if you access the prefetched pizzas like this:
topping.pizza_set.all()
If you do something like
topping.pizza_set.filter(...some conditions etc...)
then it won't work and this is expected (as only specific query result is prefetched).
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