Ticket #10161: 10161-r9848.diff

django/db/backends/__init__.py

@@ -408 +408 @@
         """
         pass
 
+    def combine_expression(self, connector, sub_expressions):
+        """Combine a list of subexpressions into a single expression, using
+        the provided connecting operator. This is required because operators
+        can vary between backends (e.g., Oracle with %% and &) and between
+        subexpression types (e.g., date expressions)
+        """
+        conn = ' %s ' % connector
+        return conn.join(sub_expressions)
+
 class BaseDatabaseIntrospection(object):
     """
     This class encapsulates all backend-specific introspection utilities

django/db/backends/oracle/base.py

@@ -221 +221 @@
         second = '%s-12-31'
         return [first % value, second % value]
 
+    def combine_expression(self, connector, sub_expressions):
+        "Oracle requires special cases for %% and & operators in query expressions"
+        if connector == '%%':
+            return 'MOD(%s)' % ','.join(sub_expressions)
+        elif:
+            return 'BITAND(%s)' % ','.join(sub_expressions)
+        return super(DatabaseOperations, self).expression(connector, sub_expressions, parameters)
 
 class DatabaseWrapper(BaseDatabaseWrapper):
 

django/db/models/sql/expressions.py

@@ -74 +74 @@
             if sql:
                 expressions.append(format % sql)
                 expression_params.extend(params)
-        conn = ' %s ' % node.connector
 
-        return conn.join(expressions), expression_params
+        return connection.ops.combine_expression(node.connector, expressions), expression_params
 
     def evaluate_leaf(self, node, qn):
         if not qn:

tests/modeltests/expressions/models.py

@@ -37 +37 @@
 >>> Company(name='Test GmbH', num_employees=32, num_chairs=1,
 ...     ceo=Employee.objects.create(firstname='Max', lastname='Mustermann')).save()
 
+>>> 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.
+>>> company_query.filter(num_employees__gt=F('num_chairs'))
+[{'num_chairs': 5, 'name': u'Example Inc.', 'num_employees': 2300}, {'num_chairs': 1, 'name': u'Test GmbH', 'num_employees': 32}]
 
->>> Company.objects.filter(num_employees__gt=F('num_chairs'))
-[<Company: Example Inc.>, <Company: Test GmbH>]
+# 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'))
+3
+>>> company_query
+[{'num_chairs': 2300, 'name': u'Example Inc.', 'num_employees': 2300}, {'num_chairs': 3, 'name': u'Foobar Ltd.', 'num_employees': 3}, {'num_chairs': 32, 'name': u'Test GmbH', 'num_employees': 32}]
 
-# The relation of a foreign key can become copied over to an other foreign key.
+# We can perform arithmetic operations in expressions
+# Make sure we have 2 spare chairs
+>>> company_query.update(num_chairs=F('num_employees')+2)
+3
+>>> company_query
+[{'num_chairs': 2302, 'name': u'Example Inc.', 'num_employees': 2300}, {'num_chairs': 5, 'name': u'Foobar Ltd.', 'num_employees': 3}, {'num_chairs': 34, 'name': u'Test GmbH', 'num_employees': 32}]
 
+# The relation of a foreign key can become copied over to an other foreign key.
 >>> Company.objects.update(point_of_contact=F('ceo'))
 3
 

tests/regressiontests/expressions_regress/models.py

@@ -1 +1 @@
 """
 Spanning tests for all the operations that F() expressions can perform.
 """
-
+from django.conf import settings
 from django.db import models
 
 #
@@ -123 +123 @@
 >>> _ = Number.objects.filter(pk=n.pk).update(integer=15 & F('integer'))
 >>> Number.objects.get(pk=n.pk) # RH Bitwise ands on integers
 <Number: 10, 15.500>
+"""}
+
+# Oracle doesn't support the Bitwise OR operator.
+if settings.DATABASE_ENGINE != 'oracle':
+    __test__['API_TESTS'] += """
 
 >>> _ = Number.objects.filter(pk=n.pk).update(integer=42, float=15.5)
 >>> _ = Number.objects.filter(pk=n.pk).update(integer=15 | F('integer'))
 >>> Number.objects.get(pk=n.pk) # RH Bitwise or on integers
 <Number: 47, 15.500>
 
-
-"""}
+"""