Made SQLCompiler.execute_sql(result_type) more explicit.

Updated SQLUpdateCompiler.execute_sql to match the behavior described in
the docstring; the 'first non-empty query' will now include all queries,
not just the main and first related update.

Added CURSOR and NO_RESULTS result_type constants to make the usages more
self documenting and allow execute_sql to explicitly close the cursor when
it is no longer needed.

1 files changed, 3 insertions, 2 deletions

diff --git a/django/db/models/query.py b/django/db/models/query.py
index 48d295ccca..353dd95794 100644
--- a/django/db/models/query.py
+++ b/django/db/models/query.py
@@ -14,6 +14,7 @@ from django.db.models.fields import AutoField, Empty
 from django.db.models.query_utils import (Q, select_related_descend,
     deferred_class_factory, InvalidQuery)
 from django.db.models.deletion import Collector
+from django.db.models.sql.constants import CURSOR
 from django.db.models import sql
 from django.utils.functional import partition
 from django.utils import six
@@ -574,7 +575,7 @@ class QuerySet(object):
         query = self.query.clone(sql.UpdateQuery)
         query.add_update_values(kwargs)
         with transaction.commit_on_success_unless_managed(using=self.db):
-            rows = query.get_compiler(self.db).execute_sql(None)
+            rows = query.get_compiler(self.db).execute_sql(CURSOR)
         self._result_cache = None
         return rows
     update.alters_data = True
@@ -591,7 +592,7 @@ class QuerySet(object):
         query = self.query.clone(sql.UpdateQuery)
         query.add_update_fields(values)
         self._result_cache = None
-        return query.get_compiler(self.db).execute_sql(None)
+        return query.get_compiler(self.db).execute_sql(CURSOR)
     _update.alters_data = True
     _update.queryset_only = False