queryset-refactor: Added ~ support to Q-objects. Based heavily on a patch from

Collin Grady. Refs #4858.


git-svn-id: http://code.djangoproject.com/svn/django/branches/queryset-refactor@6518 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/db/models/query_utils.py

@@ -40,6 +40,9 @@ class Q(tree.Node):
     def __and__(self, other):
         return self._combine(other, self.AND)
 
+    def __invert__(self):
+        return QNot(self)
+
 class QNot(Q):
     """
     Encapsulates the negation of a Q object.
@@ -50,3 +53,6 @@ class QNot(Q):
         self.add(q, self.AND)
         self.negate()
 
+    def __invert__(self):
+        return self.children[0]
+

docs/db-api.txt

@@ -211,11 +211,11 @@ Saving ForeignKey and ManyToManyField fields
 --------------------------------------------
 
 Updating ``ForeignKey`` fields works exactly the same way as saving a normal
-field; simply assign an object of the right type to the field in question:: 
+field; simply assign an object of the right type to the field in question::
 
-    cheese_blog = Blog.objects.get(name="Cheddar Talk") 
-    entry.blog = cheese_blog 
-    entry.save() 
+    cheese_blog = Blog.objects.get(name="Cheddar Talk")
+    entry.blog = cheese_blog
+    entry.save()
 
 Updating a ``ManyToManyField`` works a little differently; use the ``add()``
 method on the field to add a record to the relation::
@@ -1563,6 +1563,12 @@ This is equivalent to the following SQL ``WHERE`` clause::
 You can compose statements of arbitrary complexity by combining ``Q`` objects
 with the ``&`` and ``|`` operators. You can also use parenthetical grouping.
 
+``Q`` objects can also be negated using the ``~`` operator, allowing for
+combined lookups that combine both a normal query and a negated (``NOT``)
+query::
+
+    Q(question__startswith='Who') | ~Q(pub_date__year=2005)
+
 Each lookup function that takes keyword-arguments (e.g. ``filter()``,
 ``exclude()``, ``get()``) can also be passed one or more ``Q`` objects as
 positional (not-named) arguments. If you provide multiple ``Q`` object

tests/modeltests/or_lookups/models.py

@@ -90,6 +90,17 @@ __test__ = {'API_TESTS':"""
 >>> Article.objects.filter(Q(headline__contains='bye'), headline__startswith='Hello')
 [<Article: Hello and goodbye>]
 
+# Q objects can be negated
+>>> Article.objects.filter(Q(pk=1) | ~Q(pk=2))
+[<Article: Hello>, <Article: Hello and goodbye>]
+>>> Article.objects.filter(~Q(pk=1) & ~Q(pk=2))
+[<Article: Hello and goodbye>]
+
+# This allows for more complex queries than filter() and exclude() alone would
+# allow
+>>> Article.objects.filter(Q(pk=1) & (~Q(pk=2) | Q(pk=3)))
+[<Article: Hello>]
+
 # Try some arg queries with operations other than get_list
 >>> Article.objects.get(Q(headline__startswith='Hello'), Q(headline__contains='bye'))
 <Article: Hello and goodbye>