Skip to content

HTTPS clone URL

Subversion checkout URL

You can clone with
or
.
Download ZIP
Browse files

Fixed #16211 -- Added comparison and negation ops to F() expressions

Work done by Walter Doekes and Trac alias knoeb. Reviewed by Simon
Charette.
  • Loading branch information...
commit 28abf5f0ebc9d380f25dd278d7ef4642c4504545 1 parent ddd7d1a
@akaariai akaariai authored
View
3  django/db/backends/__init__.py
@@ -913,6 +913,9 @@ def combine_expression(self, connector, sub_expressions):
can vary between backends (e.g., Oracle with %% and &) and between
subexpression types (e.g., date expressions)
"""
+ if connector == 'NOT':
+ assert len(sub_expressions) == 1
+ return 'NOT (%s)' % sub_expressions[0]
conn = ' %s ' % connector
return conn.join(sub_expressions)
View
37 django/db/models/expressions.py
@@ -18,6 +18,17 @@ class ExpressionNode(tree.Node):
AND = '&'
OR = '|'
+ # Unary operator (needs special attention in combine_expression)
+ NOT = 'NOT'
+
+ # Comparison operators
+ EQ = '='
+ GE = '>='
+ GT = '>'
+ LE = '<='
+ LT = '<'
+ NE = '<>'
+
def __init__(self, children=None, connector=None, negated=False):
if children is not None and len(children) > 1 and connector is None:
raise TypeError('You have to specify a connector.')
@@ -93,6 +104,32 @@ def __rand__(self, other):
def __ror__(self, other):
return self._combine(other, self.OR, True)
+ def __invert__(self):
+ obj = ExpressionNode([self], connector=self.NOT, negated=True)
+ return obj
+
+ def __eq__(self, other):
+ return self._combine(other, self.EQ, False)
+
+ def __ge__(self, other):
+ return self._combine(other, self.GE, False)
+
+ def __gt__(self, other):
+ return self._combine(other, self.GT, False)
+
+ def __le__(self, other):
+ return self._combine(other, self.LE, False)
+
+ def __lt__(self, other):
+ return self._combine(other, self.LT, False)
+
+ def __ne__(self, other):
+ return self._combine(other, self.NE, False)
+
+ def __bool__(self):
+ raise TypeError('Boolean operators should be avoided. Use bitwise operators.')
+ __nonzero__ = __bool__
+
def prepare_database_save(self, unused):
return self
View
8 django/utils/tree.py
@@ -88,8 +88,12 @@ def add(self, node, conn_type):
Otherwise, the whole tree is pushed down one level and a new root
connector is created, connecting the existing tree and the new node.
"""
- if node in self.children and conn_type == self.connector:
- return
+ # Using for loop with 'is' instead of 'if node in children' so node
+ # __eq__ method doesn't get called. The __eq__ method can be overriden
+ # by subtypes, for example the F-expression.
+ for child in self.children:
+ if node is child and conn_type == self.connector:
+ return
if len(self.children) < 2:
self.connector = conn_type
if self.connector == conn_type:
View
4 docs/releases/1.5.txt
@@ -176,6 +176,10 @@ Django 1.5 also includes several smaller improvements worth noting:
:setting:`DEBUG` is `True` are sent to the console (unless you redefine the
logger in your :setting:`LOGGING` setting).
+* :ref:`F() expressions <query-expressions>` now support comparison operations
+ and inversion, expanding the types of expressions that can be passed to the
+ database.
+
Backwards incompatible changes in 1.5
=====================================
View
9 docs/topics/db/queries.txt
@@ -640,6 +640,15 @@ that were modified more than 3 days after they were published::
>>> from datetime import timedelta
>>> Entry.objects.filter(mod_date__gt=F('pub_date') + timedelta(days=3))
+.. versionadded:: 1.5
+ Comparisons and negation operators for ``F()`` expressions
+
+Django also supports the comparison operators ``==``, ``!=``, ``<=``, ``<``,
+``>``, ``>=`` and the bitwise negation operator ``~`` (boolean ``not`` operator
+will raise ``TypeError``)::
+
+ >>> Entry.objects.filter(is_heavily_quoted=~(F('n_pingbacks') < 100))
+
The pk lookup shortcut
----------------------
View
2  tests/modeltests/expressions/models.py
@@ -27,6 +27,8 @@ class Company(models.Model):
Employee,
related_name='company_point_of_contact_set',
null=True)
+ is_large = models.BooleanField(
+ blank=True)
def __str__(self):
return self.name
View
109 tests/modeltests/expressions/tests.py
@@ -11,22 +11,22 @@
class ExpressionsTests(TestCase):
def test_filter(self):
Company.objects.create(
- name="Example Inc.", num_employees=2300, num_chairs=5,
+ name="Example Inc.", num_employees=2300, num_chairs=5, is_large=False,
ceo=Employee.objects.create(firstname="Joe", lastname="Smith")
)
Company.objects.create(
- name="Foobar Ltd.", num_employees=3, num_chairs=4,
+ name="Foobar Ltd.", num_employees=3, num_chairs=4, is_large=False,
ceo=Employee.objects.create(firstname="Frank", lastname="Meyer")
)
Company.objects.create(
- name="Test GmbH", num_employees=32, num_chairs=1,
+ name="Test GmbH", num_employees=32, num_chairs=1, is_large=False,
ceo=Employee.objects.create(firstname="Max", lastname="Mustermann")
)
company_query = Company.objects.values(
- "name", "num_employees", "num_chairs"
+ "name", "num_employees", "num_chairs", "is_large"
).order_by(
- "name", "num_employees", "num_chairs"
+ "name", "num_employees", "num_chairs", "is_large"
)
# We can filter for companies where the number of employees is greater
@@ -37,11 +37,13 @@ def test_filter(self):
"num_chairs": 5,
"name": "Example Inc.",
"num_employees": 2300,
+ "is_large": False
},
{
"num_chairs": 1,
"name": "Test GmbH",
- "num_employees": 32
+ "num_employees": 32,
+ "is_large": False
},
],
lambda o: o
@@ -55,17 +57,20 @@ def test_filter(self):
{
"num_chairs": 2300,
"name": "Example Inc.",
- "num_employees": 2300
+ "num_employees": 2300,
+ "is_large": False
},
{
"num_chairs": 3,
"name": "Foobar Ltd.",
- "num_employees": 3
+ "num_employees": 3,
+ "is_large": False
},
{
"num_chairs": 32,
"name": "Test GmbH",
- "num_employees": 32
+ "num_employees": 32,
+ "is_large": False
}
],
lambda o: o
@@ -79,17 +84,20 @@ def test_filter(self):
{
'num_chairs': 2302,
'name': 'Example Inc.',
- 'num_employees': 2300
+ 'num_employees': 2300,
+ 'is_large': False
},
{
'num_chairs': 5,
'name': 'Foobar Ltd.',
- 'num_employees': 3
+ 'num_employees': 3,
+ 'is_large': False
},
{
'num_chairs': 34,
'name': 'Test GmbH',
- 'num_employees': 32
+ 'num_employees': 32,
+ 'is_large': False
}
],
lambda o: o,
@@ -104,17 +112,20 @@ def test_filter(self):
{
'num_chairs': 6900,
'name': 'Example Inc.',
- 'num_employees': 2300
+ 'num_employees': 2300,
+ 'is_large': False
},
{
'num_chairs': 9,
'name': 'Foobar Ltd.',
- 'num_employees': 3
+ 'num_employees': 3,
+ 'is_large': False
},
{
'num_chairs': 96,
'name': 'Test GmbH',
- 'num_employees': 32
+ 'num_employees': 32,
+ 'is_large': False
}
],
lambda o: o,
@@ -129,21 +140,80 @@ def test_filter(self):
{
'num_chairs': 5294600,
'name': 'Example Inc.',
- 'num_employees': 2300
+ 'num_employees': 2300,
+ 'is_large': False
},
{
'num_chairs': 15,
'name': 'Foobar Ltd.',
- 'num_employees': 3
+ 'num_employees': 3,
+ 'is_large': False
},
{
'num_chairs': 1088,
'name': 'Test GmbH',
- 'num_employees': 32
+ 'num_employees': 32,
+ 'is_large': False
}
],
lambda o: o,
)
+ # The comparison operators and the bitwise unary not can be used
+ # to assign to boolean fields
+ for expression in (
+ # Check boundaries
+ ~(F('num_employees') < 33),
+ ~(F('num_employees') <= 32),
+ (F('num_employees') > 2299),
+ (F('num_employees') >= 2300),
+ (F('num_employees') == 2300),
+ ((F('num_employees') + 1 != 4) & (32 != F('num_employees'))),
+ # Inverted argument order works too
+ (2299 < F('num_employees')),
+ (2300 <= F('num_employees'))
+ ):
+ # Test update by F-expression
+ company_query.update(
+ is_large=expression
+ )
+ # Compare results
+ self.assertQuerysetEqual(
+ company_query, [
+ {
+ 'num_chairs': 5294600,
+ 'name': 'Example Inc.',
+ 'num_employees': 2300,
+ 'is_large': True
+ },
+ {
+ 'num_chairs': 15,
+ 'name': 'Foobar Ltd.',
+ 'num_employees': 3,
+ 'is_large': False
+ },
+ {
+ 'num_chairs': 1088,
+ 'name': 'Test GmbH',
+ 'num_employees': 32,
+ 'is_large': False
+ }
+ ],
+ lambda o: o,
+ )
+ # Reset values
+ company_query.update(
+ is_large=False
+ )
+
+ # The python boolean operators should be avoided as they yield
+ # unexpected results
+ test_gmbh = Company.objects.get(name="Test GmbH")
+ with self.assertRaises(TypeError):
+ test_gmbh.is_large = not F('is_large')
+ with self.assertRaises(TypeError):
+ test_gmbh.is_large = F('is_large') and F('is_large')
+ with self.assertRaises(TypeError):
+ test_gmbh.is_large = F('is_large') or F('is_large')
# The relation of a foreign key can become copied over to an other
# foreign key.
@@ -202,9 +272,8 @@ def test_filter(self):
test_gmbh.point_of_contact = None
test_gmbh.save()
self.assertTrue(test_gmbh.point_of_contact is None)
- def test():
+ with self.assertRaises(ValueError):
test_gmbh.point_of_contact = F("ceo")
- self.assertRaises(ValueError, test)
test_gmbh.point_of_contact = test_gmbh.ceo
test_gmbh.save()
Please sign in to comment.
Something went wrong with that request. Please try again.