mirror of
https://github.com/django/django.git
synced 2024-12-23 09:36:06 +00:00
263 lines
9.1 KiB
Python
263 lines
9.1 KiB
Python
from __future__ import unicode_literals
|
|
|
|
from django.core.exceptions import FieldError
|
|
from django.db.models import F
|
|
from django.test import TestCase
|
|
from django.utils import six
|
|
|
|
from .models import Company, Employee
|
|
|
|
|
|
class ExpressionsTests(TestCase):
|
|
def test_filter(self):
|
|
Company.objects.create(
|
|
name="Example Inc.", num_employees=2300, num_chairs=5,
|
|
ceo=Employee.objects.create(firstname="Joe", lastname="Smith")
|
|
)
|
|
Company.objects.create(
|
|
name="Foobar Ltd.", num_employees=3, num_chairs=4,
|
|
ceo=Employee.objects.create(firstname="Frank", lastname="Meyer")
|
|
)
|
|
Company.objects.create(
|
|
name="Test GmbH", num_employees=32, num_chairs=1,
|
|
ceo=Employee.objects.create(firstname="Max", lastname="Mustermann")
|
|
)
|
|
|
|
company_query = Company.objects.values(
|
|
"name", "num_employees", "num_chairs"
|
|
).order_by(
|
|
"name", "num_employees", "num_chairs"
|
|
)
|
|
|
|
# We can filter for companies where the number of employees is greater
|
|
# than the number of chairs.
|
|
self.assertQuerysetEqual(
|
|
company_query.filter(num_employees__gt=F("num_chairs")), [
|
|
{
|
|
"num_chairs": 5,
|
|
"name": "Example Inc.",
|
|
"num_employees": 2300,
|
|
},
|
|
{
|
|
"num_chairs": 1,
|
|
"name": "Test GmbH",
|
|
"num_employees": 32
|
|
},
|
|
],
|
|
lambda o: o
|
|
)
|
|
|
|
# We can set one field to have the value of another field
|
|
# Make sure we have enough chairs
|
|
company_query.update(num_chairs=F("num_employees"))
|
|
self.assertQuerysetEqual(
|
|
company_query, [
|
|
{
|
|
"num_chairs": 2300,
|
|
"name": "Example Inc.",
|
|
"num_employees": 2300
|
|
},
|
|
{
|
|
"num_chairs": 3,
|
|
"name": "Foobar Ltd.",
|
|
"num_employees": 3
|
|
},
|
|
{
|
|
"num_chairs": 32,
|
|
"name": "Test GmbH",
|
|
"num_employees": 32
|
|
}
|
|
],
|
|
lambda o: o
|
|
)
|
|
|
|
# We can perform arithmetic operations in expressions
|
|
# Make sure we have 2 spare chairs
|
|
company_query.update(num_chairs=F("num_employees")+2)
|
|
self.assertQuerysetEqual(
|
|
company_query, [
|
|
{
|
|
'num_chairs': 2302,
|
|
'name': 'Example Inc.',
|
|
'num_employees': 2300
|
|
},
|
|
{
|
|
'num_chairs': 5,
|
|
'name': 'Foobar Ltd.',
|
|
'num_employees': 3
|
|
},
|
|
{
|
|
'num_chairs': 34,
|
|
'name': 'Test GmbH',
|
|
'num_employees': 32
|
|
}
|
|
],
|
|
lambda o: o,
|
|
)
|
|
|
|
# Law of order of operations is followed
|
|
company_query.update(
|
|
num_chairs=F('num_employees') + 2 * F('num_employees')
|
|
)
|
|
self.assertQuerysetEqual(
|
|
company_query, [
|
|
{
|
|
'num_chairs': 6900,
|
|
'name': 'Example Inc.',
|
|
'num_employees': 2300
|
|
},
|
|
{
|
|
'num_chairs': 9,
|
|
'name': 'Foobar Ltd.',
|
|
'num_employees': 3
|
|
},
|
|
{
|
|
'num_chairs': 96,
|
|
'name': 'Test GmbH',
|
|
'num_employees': 32
|
|
}
|
|
],
|
|
lambda o: o,
|
|
)
|
|
|
|
# Law of order of operations can be overridden by parentheses
|
|
company_query.update(
|
|
num_chairs=((F('num_employees') + 2) * F('num_employees'))
|
|
)
|
|
self.assertQuerysetEqual(
|
|
company_query, [
|
|
{
|
|
'num_chairs': 5294600,
|
|
'name': 'Example Inc.',
|
|
'num_employees': 2300
|
|
},
|
|
{
|
|
'num_chairs': 15,
|
|
'name': 'Foobar Ltd.',
|
|
'num_employees': 3
|
|
},
|
|
{
|
|
'num_chairs': 1088,
|
|
'name': 'Test GmbH',
|
|
'num_employees': 32
|
|
}
|
|
],
|
|
lambda o: o,
|
|
)
|
|
|
|
# The relation of a foreign key can become copied over to an other
|
|
# foreign key.
|
|
self.assertEqual(
|
|
Company.objects.update(point_of_contact=F('ceo')),
|
|
3
|
|
)
|
|
self.assertQuerysetEqual(
|
|
Company.objects.all(), [
|
|
"Joe Smith",
|
|
"Frank Meyer",
|
|
"Max Mustermann",
|
|
],
|
|
lambda c: six.text_type(c.point_of_contact),
|
|
ordered=False
|
|
)
|
|
|
|
c = Company.objects.all()[0]
|
|
c.point_of_contact = Employee.objects.create(firstname="Guido", lastname="van Rossum")
|
|
c.save()
|
|
|
|
# F Expressions can also span joins
|
|
self.assertQuerysetEqual(
|
|
Company.objects.filter(ceo__firstname=F("point_of_contact__firstname")), [
|
|
"Foobar Ltd.",
|
|
"Test GmbH",
|
|
],
|
|
lambda c: c.name,
|
|
ordered=False
|
|
)
|
|
|
|
Company.objects.exclude(
|
|
ceo__firstname=F("point_of_contact__firstname")
|
|
).update(name="foo")
|
|
self.assertEqual(
|
|
Company.objects.exclude(
|
|
ceo__firstname=F('point_of_contact__firstname')
|
|
).get().name,
|
|
"foo",
|
|
)
|
|
|
|
self.assertRaises(FieldError,
|
|
lambda: Company.objects.exclude(
|
|
ceo__firstname=F('point_of_contact__firstname')
|
|
).update(name=F('point_of_contact__lastname'))
|
|
)
|
|
|
|
# F expressions can be used to update attributes on single objects
|
|
test_gmbh = Company.objects.get(name="Test GmbH")
|
|
self.assertEqual(test_gmbh.num_employees, 32)
|
|
test_gmbh.num_employees = F("num_employees") + 4
|
|
test_gmbh.save()
|
|
test_gmbh = Company.objects.get(pk=test_gmbh.pk)
|
|
self.assertEqual(test_gmbh.num_employees, 36)
|
|
|
|
# F expressions cannot be used to update attributes which are foreign
|
|
# keys, or attributes which involve joins.
|
|
test_gmbh.point_of_contact = None
|
|
test_gmbh.save()
|
|
self.assertTrue(test_gmbh.point_of_contact is None)
|
|
def test():
|
|
test_gmbh.point_of_contact = F("ceo")
|
|
self.assertRaises(ValueError, test)
|
|
|
|
test_gmbh.point_of_contact = test_gmbh.ceo
|
|
test_gmbh.save()
|
|
test_gmbh.name = F("ceo__last_name")
|
|
self.assertRaises(FieldError, test_gmbh.save)
|
|
|
|
# F expressions cannot be used to update attributes on objects which do
|
|
# not yet exist in the database
|
|
acme = Company(
|
|
name="The Acme Widget Co.", num_employees=12, num_chairs=5,
|
|
ceo=test_gmbh.ceo
|
|
)
|
|
acme.num_employees = F("num_employees") + 16
|
|
self.assertRaises(TypeError, acme.save)
|
|
|
|
def test_ticket_18375_join_reuse(self):
|
|
# Test that reverse multijoin F() references and the lookup target
|
|
# the same join. Pre #18375 the F() join was generated first, and the
|
|
# lookup couldn't reuse that join.
|
|
qs = Employee.objects.filter(
|
|
company_ceo_set__num_chairs=F('company_ceo_set__num_employees'))
|
|
self.assertEqual(str(qs.query).count('JOIN'), 1)
|
|
|
|
def test_ticket_18375_kwarg_ordering(self):
|
|
# The next query was dict-randomization dependent - if the "gte=1"
|
|
# was seen first, then the F() will reuse the join generated by the
|
|
# gte lookup, if F() was seen first, then it generated a join the
|
|
# other lookups could not reuse.
|
|
qs = Employee.objects.filter(
|
|
company_ceo_set__num_chairs=F('company_ceo_set__num_employees'),
|
|
company_ceo_set__num_chairs__gte=1)
|
|
self.assertEqual(str(qs.query).count('JOIN'), 1)
|
|
|
|
def test_ticket_18375_kwarg_ordering_2(self):
|
|
# Another similar case for F() than above. Now we have the same join
|
|
# in two filter kwargs, one in the lhs lookup, one in F. Here pre
|
|
# #18375 the amount of joins generated was random if dict
|
|
# randomization was enabled, that is the generated query dependend
|
|
# on which clause was seen first.
|
|
qs = Employee.objects.filter(
|
|
company_ceo_set__num_employees=F('pk'),
|
|
pk=F('company_ceo_set__num_employees')
|
|
)
|
|
self.assertEqual(str(qs.query).count('JOIN'), 1)
|
|
|
|
def test_ticket_18375_chained_filters(self):
|
|
# Test that F() expressions do not reuse joins from previous filter.
|
|
qs = Employee.objects.filter(
|
|
company_ceo_set__num_employees=F('pk')
|
|
).filter(
|
|
company_ceo_set__num_employees=F('company_ceo_set__num_employees')
|
|
)
|
|
self.assertEqual(str(qs.query).count('JOIN'), 2)
|