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Fixed #17027 -- Added support for the power operator in F expressions.

Thanks dan at dlo.me for the initial patch.

- Added __pow__ and __rpow__ to ExpressionNode
- Added oracle and mysql specific power expressions
- Added used-defined power function for sqlite
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commit 5240b83462ba4887b67da8d493dfdc23fec5df97 1 parent 1597503
@fhahn fhahn authored timgraham committed
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8 django/db/backends/mysql/base.py
@@ -386,6 +386,14 @@ def bulk_insert_sql(self, fields, num_values):
items_sql = "(%s)" % ", ".join(["%s"] * len(fields))
return "VALUES " + ", ".join([items_sql] * num_values)
+ def combine_expression(self, connector, sub_expressions):
+ """
+ MySQL requires special cases for ^ operators in query expressions
+ """
+ if connector == '^':
+ return 'POW(%s)' % ','.join(sub_expressions)
+ return super(DatabaseOperations, self).combine_expression(connector, sub_expressions)
+
class DatabaseWrapper(BaseDatabaseWrapper):
vendor = 'mysql'
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2  django/db/backends/oracle/base.py
@@ -482,6 +482,8 @@ def combine_expression(self, connector, sub_expressions):
return 'BITAND(%s)' % ','.join(sub_expressions)
elif connector == '|':
raise NotImplementedError("Bit-wise or is not supported in Oracle.")
+ elif connector == '^':
+ return 'POWER(%s)' % ','.join(sub_expressions)
return super(DatabaseOperations, self).combine_expression(connector, sub_expressions)
def _get_sequence_name(self, table):
View
12 django/db/backends/sqlite3/base.py
@@ -304,6 +304,13 @@ def bulk_insert_sql(self, fields, num_values):
res.extend(["UNION ALL SELECT %s" % ", ".join(["%s"] * len(fields))] * (num_values - 1))
return " ".join(res)
+ def combine_expression(self, connector, sub_expressions):
+ # SQLite doesn't have a power function, so we fake it with a
+ # user-defined function django_power that's registered in connect().
+ if connector == '^':
+ return 'django_power(%s)' % ','.join(sub_expressions)
+ return super(DatabaseOperations, self).combine_expression(connector, sub_expressions)
+
class DatabaseWrapper(BaseDatabaseWrapper):
vendor = 'sqlite'
@@ -376,6 +383,7 @@ def get_new_connection(self, conn_params):
conn.create_function("django_datetime_trunc", 3, _sqlite_datetime_trunc)
conn.create_function("regexp", 2, _sqlite_regexp)
conn.create_function("django_format_dtdelta", 5, _sqlite_format_dtdelta)
+ conn.create_function("django_power", 2, _sqlite_power)
return conn
def init_connection_state(self):
@@ -567,3 +575,7 @@ def _sqlite_format_dtdelta(dt, conn, days, secs, usecs):
def _sqlite_regexp(re_pattern, re_string):
return bool(re.search(re_pattern, force_text(re_string))) if re_string is not None else False
+
+
+def _sqlite_power(x, y):
+ return x ** y
View
7 django/db/models/expressions.py
@@ -14,6 +14,7 @@ class ExpressionNode(tree.Node):
SUB = '-'
MUL = '*'
DIV = '/'
+ POW = '^'
MOD = '%%' # This is a quoted % operator - it is quoted
# because it can be used in strings that also
# have parameter substitution.
@@ -85,6 +86,9 @@ def __div__(self, other): # Python 2 compatibility
def __mod__(self, other):
return self._combine(other, self.MOD, False)
+ def __pow__(self, other):
+ return self._combine(other, self.POW, False)
+
def __and__(self, other):
raise NotImplementedError(
"Use .bitand() and .bitor() for bitwise logical operations."
@@ -119,6 +123,9 @@ def __rdiv__(self, other): # Python 2 compatibility
def __rmod__(self, other):
return self._combine(other, self.MOD, True)
+ def __rpow__(self, other):
+ return self._combine(other, self.POW, True)
+
def __rand__(self, other):
raise NotImplementedError(
"Use .bitand() and .bitor() for bitwise logical operations."
View
4 docs/ref/models/queries.txt
@@ -112,6 +112,10 @@ As well as addition, Django supports subtraction, multiplication, division,
and modulo arithmetic with ``F()`` objects, using Python constants,
variables, and even other ``F()`` objects.
+.. versionadded:: 1.7
+
+ The power operator ``**`` is also supported.
+
``Q()`` objects
===============
View
3  docs/releases/1.7.txt
@@ -346,6 +346,9 @@ Models
:attr:`~django.db.models.ForeignKey.related_name` to
`'+'` or ending it with `'+'`.
+* :class:`F expressions <django.db.models.F>` support the power operator
+ (``**``).
+
Signals
^^^^^^^
View
6 docs/topics/db/queries.txt
@@ -610,12 +610,16 @@ and use that ``F()`` object in the query::
>>> Entry.objects.filter(n_comments__gt=F('n_pingbacks'))
Django supports the use of addition, subtraction, multiplication,
-division and modulo arithmetic with ``F()`` objects, both with constants
+division, modulo, and power arithmetic with ``F()`` objects, both with constants
and with other ``F()`` objects. To find all the blog entries with more than
*twice* as many comments as pingbacks, we modify the query::
>>> Entry.objects.filter(n_comments__gt=F('n_pingbacks') * 2)
+.. versionadded:: 1.7
+
+ The power operator ``**`` was added.
+
To find all the entries where the rating of the entry is less than the
sum of the pingback count and comment count, we would issue the
query::
View
2  tests/expressions_regress/models.py
@@ -8,7 +8,7 @@
@python_2_unicode_compatible
class Number(models.Model):
- integer = models.IntegerField(db_column='the_integer')
+ integer = models.BigIntegerField(db_column='the_integer')
float = models.FloatField(null=True, db_column='the_float')
def __str__(self):
View
14 tests/expressions_regress/tests.py
@@ -145,6 +145,13 @@ def test_lefthand_bitwise_or(self):
self.assertEqual(Number.objects.get(pk=self.n.pk).integer, 58)
self.assertEqual(Number.objects.get(pk=self.n.pk).float, Approximate(15.500, places=3))
+ def test_lefthand_power(self):
+ # LH Powert arithmetic operation on floats and integers
+ Number.objects.filter(pk=self.n.pk).update(integer=F('integer') ** 2,
+ float=F('float') ** 1.5)
+ self.assertEqual(Number.objects.get(pk=self.n.pk).integer, 1764)
+ self.assertEqual(Number.objects.get(pk=self.n.pk).float, Approximate(61.02, places=2))
+
def test_right_hand_addition(self):
# Right hand operators
Number.objects.filter(pk=self.n.pk).update(integer=15 + F('integer'),
@@ -185,6 +192,13 @@ def test_right_hand_modulo(self):
self.assertEqual(Number.objects.get(pk=self.n.pk).integer, 27)
self.assertEqual(Number.objects.get(pk=self.n.pk).float, Approximate(15.500, places=3))
+ def test_righthand_power(self):
+ # RH Powert arithmetic operation on floats and integers
+ Number.objects.filter(pk=self.n.pk).update(integer=2 ** F('integer'),
+ float=1.5 ** F('float'))
+ self.assertEqual(Number.objects.get(pk=self.n.pk).integer, 4398046511104)
+ self.assertEqual(Number.objects.get(pk=self.n.pk).float, Approximate(536.308, places=3))
+
class FTimeDeltaTests(TestCase):
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