id	summary	reporter	owner	description	type	status	component	version	severity	resolution	keywords	cc	stage	has_patch	needs_docs	needs_tests	needs_better_patch	easy	ui_ux
9394	Reverse relation lookups with 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."	Cleanup/optimization	closed	Database layer (models, ORM)	dev	Normal	duplicate			Accepted	1	0	0	1	0	0