Commit 5240b834 authored by Florian Hahn's avatar Florian Hahn Committed by Tim Graham
Browse files

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
parent 1597503a

django/db/backends/mysql/base.py

+8 −0
Original line number Diff line number Diff line
@@ -386,6 +386,14 @@ class DatabaseOperations(BaseDatabaseOperations): 
        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'

django/db/backends/oracle/base.py

+2 −0
Original line number Diff line number Diff line
@@ -482,6 +482,8 @@ WHEN (new.%(col_name)s IS NULL) 
            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):

django/db/backends/sqlite3/base.py

+12 −0
Original line number Diff line number Diff line
@@ -304,6 +304,13 @@ class DatabaseOperations(BaseDatabaseOperations): 
        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 @@ class DatabaseWrapper(BaseDatabaseWrapper): 
        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

django/db/models/expressions.py

+7 −0
Original line number Diff line number Diff line
@@ -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 @@ class ExpressionNode(tree.Node): 
    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 @@ class ExpressionNode(tree.Node): 
    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."

docs/ref/models/queries.txt

+4 −0
Original line number Diff line number Diff line
@@ -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

===============