queryset-refactor: Made the use of values() for ForeignKey fields consistent

and documented this feature. Refs #4358.


git-svn-id: http://code.djangoproject.com/svn/django/branches/queryset-refactor@6516 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/db/models/query.py

@@ -391,17 +391,22 @@ class ValuesQuerySet(QuerySet):
         # 'fields' is used to configure the query, whilst field_names is stored
         # in this object for use by iterator().
         if self._fields:
+            opts = self.model._meta
+            all = dict([(field.column, field) for field in opts.fields])
+            all.update([(field.name, field) for field in opts.fields])
             if not self.query.extra_select:
-                fields = [self.model._meta.get_field(f, many_to_many=False)
-                        for f in self._fields]
+                try:
+                    fields = [all[f] for f in self._fields]
+                except KeyError, e:
+                    raise FieldDoesNotExist('%s has no field named %r'
+                                % (opts.object_name, e.args[0]))
                 field_names = self._fields
             else:
                 fields = []
                 field_names = []
                 for f in self._fields:
-                    if f in [field.name for field in self.model._meta.fields]:
-                        fields.append(self.model._meta.get_field(f,
-                                many_to_many=False))
+                    if f in all:
+                        fields.append(all[f])
                         field_names.append(f)
                     elif not self.query.extra_select.has_key(f):
                         raise FieldDoesNotExist('%s has no field named %r'

docs/db-api.txt

@@ -583,6 +583,30 @@ Example::
     >>> Blog.objects.values('id', 'name')
     [{'id': 1, 'name': 'Beatles Blog'}]
 
+A couple of subtleties that are worth mentioning:
+
+    * The ``values()`` method does not return anything for ``ManyToManyField``
+      attributes and will raise an error if you try to pass in this type of
+      field to it.
+    * If you have a field called ``foo`` that is a ``ForeignKey``, the default
+      ``values()`` call will return a dictionary key called ``foo_id``, since
+      this is the name of the hidden model attribute that stores the actual
+      value (the ``foo`` attribute refers to the related model). When you are
+      calling ``values()`` and passing in field names, you can pass in either
+      ``foo`` or ``foo_id`` and you will get back the same thing (the
+      dictionary key will match the field name you passed in).
+
+      For example::
+
+        >>> Entry.objects.values()
+        [{'blog_id: 1, 'headline': u'First Entry', ...}, ...]
+
+        >>> Entry.objects.values('blog')
+        [{'blog': 1}, ...]
+
+        >>> Entry.objects.values('blog_id')
+        [{'blog_id': 1}, ...]
+
 A ``ValuesQuerySet`` is useful when you know you're only going to need values
 from a small number of the available fields and you won't need the
 functionality of a model instance object. It's more efficient to select only

tests/regressiontests/queries/models.py

@@ -334,5 +334,24 @@ Bug #3037
 Bug #5321
 >>> Note.objects.values('misc').distinct().order_by('note', '-misc')
 [{'misc': u'foo'}, {'misc': u'bar'}]
+
+Bug #4358
+If you don't pass any fields to values(), relation fields are returned as
+"foo_id" keys, not "foo". For consistency, you should be able to pass "foo_id"
+in the fields list and have it work, too. We actually allow both "foo" and
+"foo_id".
+
+# The *_id version is returned by default.
+>>> 'note_id' in ExtraInfo.objects.values()[0]
+True
+
+# You can also pass it in explicitly.
+>>> ExtraInfo.objects.values('note_id')
+[{'note_id': 1}, {'note_id': 2}]
+
+# ...or use the field name.
+>>> ExtraInfo.objects.values('note')
+[{'note': 1}, {'note': 2}]
+
 """}