Fixed #1142 -- Added multiple database support.

This monster of a patch is the result of Alex Gaynor's 2009 Google Summer of Code project.
Congratulations to Alex for a job well done.

Big thanks also go to:
 * Justin Bronn for keeping GIS in line with the changes,
 * Karen Tracey and Jani Tiainen for their help testing Oracle support
 * Brett Hoerner, Jon Loyens, and Craig Kimmerer for their feedback.
 * Malcolm Treddinick for his guidance during the GSoC submission process.
 * Simon Willison for driving the original design process
 * Cal Henderson for complaining about ponies he wanted.

... and everyone else too numerous to mention that helped to bring this feature into fruition.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@11952 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/forms/models.py

@@ -3,6 +3,7 @@ Helper functions for creating Form classes from Django models
 and database field objects.
 """
 
+from django.db import connections
 from django.utils.encoding import smart_unicode, force_unicode
 from django.utils.datastructures import SortedDict
 from django.utils.text import get_text_list, capfirst
@@ -470,7 +471,8 @@ class BaseModelFormSet(BaseFormSet):
             pk_key = "%s-%s" % (self.add_prefix(i), self.model._meta.pk.name)
             pk = self.data[pk_key]
             pk_field = self.model._meta.pk
-            pk = pk_field.get_db_prep_lookup('exact', pk)
+            pk = pk_field.get_db_prep_lookup('exact', pk,
+                connection=connections[self.get_queryset().db])
             if isinstance(pk, list):
                 pk = pk[0]
             kwargs['instance'] = self._existing_object(pk)
@@ -679,6 +681,7 @@ class BaseModelFormSet(BaseFormSet):
                 qs = pk.rel.to._default_manager.get_query_set()
             else:
                 qs = self.model._default_manager.get_query_set()
+            qs = qs.using(form.instance._state.db)
             form.fields[self._pk_field.name] = ModelChoiceField(qs, initial=pk_value, required=False, widget=HiddenInput)
         super(BaseModelFormSet, self).add_fields(form, index)