Querying a many-to-many intermediate model from a manager on a multi-table inherited model produces extraneous queries

[Erin Kelly]

With the following models:

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

class Business(Place):
    owner = models.CharField(max_length=50)

class Restaurant(Business):
    rating = models.IntegerField()

class Chef(models.Model):
    name = models.CharField(max_length=50)
    restaurants = models.ManyToManyField(Restaurant, through='Employee')

class Employee(models.Model):
    restaurant = models.ForeignKey(Restaurant)
    chef = models.ForeignKey(Chef)
    years_of_service = models.IntegerField()

we can do some_restaurant.employee_set.all(), which results in three queries. The first two queries are just retrieving the attributes of the inherited Business and Place models, which is unnecessary since all that information already exists on the some_restaurant object. Only one query should be needed.

[Erin Kelly]

The occurrences of ChineseRestaurant in the models should just be Restaurant. Sorry about that.

[Ramiro Morales]

(edited code example in the description as per Ian's note above, replacing ChineseRestaurant with Restaurant.)