django/tests/regressiontests/select_related_regress/models.py

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from django.db import models
class Building(models.Model):
name = models.CharField(max_length=10)
def __unicode__(self):
return u"Building: %s" % self.name
class Device(models.Model):
building = models.ForeignKey('Building')
name = models.CharField(max_length=10)
def __unicode__(self):
return u"device '%s' in building %s" % (self.name, self.building)
class Port(models.Model):
device = models.ForeignKey('Device')
port_number = models.CharField(max_length=10)
def __unicode__(self):
return u"%s/%s" % (self.device.name, self.port_number)
class Connection(models.Model):
start = models.ForeignKey(Port, related_name='connection_start',
unique=True)
end = models.ForeignKey(Port, related_name='connection_end', unique=True)
def __unicode__(self):
return u"%s to %s" % (self.start, self.end)
# Another non-tree hierarchy that exercises code paths similar to the above
# example, but in a slightly different configuration.
class TUser(models.Model):
name = models.CharField(max_length=200)
class Person(models.Model):
user = models.ForeignKey(TUser, unique=True)
class Organizer(models.Model):
person = models.ForeignKey(Person)
class Student(models.Model):
person = models.ForeignKey(Person)
class Class(models.Model):
org = models.ForeignKey(Organizer)
class Enrollment(models.Model):
std = models.ForeignKey(Student)
cls = models.ForeignKey(Class)
# Models for testing bug #8036.
class Country(models.Model):
name = models.CharField(max_length=50)
class State(models.Model):
name = models.CharField(max_length=50)
country = models.ForeignKey(Country)
class ClientStatus(models.Model):
name = models.CharField(max_length=50)
class Client(models.Model):
name = models.CharField(max_length=50)
state = models.ForeignKey(State, null=True)
status = models.ForeignKey(ClientStatus)
__test__ = {'API_TESTS': """
Regression test for bug #7110. When using select_related(), we must query the
Device and Building tables using two different aliases (each) in order to
differentiate the start and end Connection fields. The net result is that both
the "connections = ..." queries here should give the same results without
pulling in more than the absolute minimum number of tables (history has
shown that it's easy to make a mistake in the implementation and include some
unnecessary bonus joins).
>>> b=Building.objects.create(name='101')
>>> dev1=Device.objects.create(name="router", building=b)
>>> dev2=Device.objects.create(name="switch", building=b)
>>> dev3=Device.objects.create(name="server", building=b)
>>> port1=Port.objects.create(port_number='4',device=dev1)
>>> port2=Port.objects.create(port_number='7',device=dev2)
>>> port3=Port.objects.create(port_number='1',device=dev3)
>>> c1=Connection.objects.create(start=port1, end=port2)
>>> c2=Connection.objects.create(start=port2, end=port3)
>>> connections=Connection.objects.filter(start__device__building=b, end__device__building=b).order_by('id')
>>> [(c.id, unicode(c.start), unicode(c.end)) for c in connections]
[(1, u'router/4', u'switch/7'), (2, u'switch/7', u'server/1')]
>>> connections=Connection.objects.filter(start__device__building=b, end__device__building=b).select_related().order_by('id')
>>> [(c.id, unicode(c.start), unicode(c.end)) for c in connections]
[(1, u'router/4', u'switch/7'), (2, u'switch/7', u'server/1')]
# This final query should only join seven tables (port, device and building
# twice each, plus connection once).
>>> connections.query.count_active_tables()
7
Regression test for bug #8106. Same sort of problem as the previous test, but
this time there are more extra tables to pull in as part of the
select_related() and some of them could potentially clash (so need to be kept
separate).
>>> us = TUser.objects.create(name="std")
>>> usp = Person.objects.create(user=us)
>>> uo = TUser.objects.create(name="org")
>>> uop = Person.objects.create(user=uo)
>>> s = Student.objects.create(person = usp)
>>> o = Organizer.objects.create(person = uop)
>>> c = Class.objects.create(org=o)
>>> e = Enrollment.objects.create(std=s, cls=c)
>>> e_related = Enrollment.objects.all().select_related()[0]
>>> e_related.std.person.user.name
u"std"
>>> e_related.cls.org.person.user.name
u"org"
Regression test for bug #8036: the first related model in the tests below
("state") is empty and we try to select the more remotely related
state__country. The regression here was not skipping the empty column results
for country before getting status.
>>> australia = Country.objects.create(name='Australia')
>>> active = ClientStatus.objects.create(name='active')
>>> client = Client.objects.create(name='client', status=active)
>>> client.status
<ClientStatus: ClientStatus object>
>>> Client.objects.select_related()[0].status
<ClientStatus: ClientStatus object>
>>> Client.objects.select_related('state')[0].status
<ClientStatus: ClientStatus object>
>>> Client.objects.select_related('state', 'status')[0].status
<ClientStatus: ClientStatus object>
>>> Client.objects.select_related('state__country')[0].status
<ClientStatus: ClientStatus object>
>>> Client.objects.select_related('state__country', 'status')[0].status
<ClientStatus: ClientStatus object>
>>> Client.objects.select_related('status')[0].status
<ClientStatus: ClientStatus object>
"""}