Fixed #11402: added a `QuerySet.exists()` method. Thanks, Alex Gaynor.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@11646 bcc190cf-cafb-0310-a4f2-bffc1f526a37

1 files changed, 1 insertions, 8 deletions

diff --git a/django/db/models/base.py b/django/db/models/base.py
index a5c99865a6..1e081ae92e 100644
--- a/django/db/models/base.py
+++ b/django/db/models/base.py
@@ -3,11 +3,6 @@ import types
 import sys
 import os
 from itertools import izip
-try:
-    set
-except NameError:
-    from sets import Set as set     # Python 2.3 fallback.
-
 import django.db.models.manager     # Imported to register signal handler.
 from django.core.exceptions import ObjectDoesNotExist, MultipleObjectsReturned, FieldError
 from django.db.models.fields import AutoField, FieldDoesNotExist
@@ -22,7 +17,6 @@ from django.utils.functional import curry
 from django.utils.encoding import smart_str, force_unicode, smart_unicode
 from django.conf import settings
 
-
 class ModelBase(type):
     """
     Metaclass for all models.
@@ -236,7 +230,6 @@ class ModelBase(type):
 
         signals.class_prepared.send(sender=cls)
 
-
 class Model(object):
     __metaclass__ = ModelBase
     _deferred = False
@@ -467,7 +460,7 @@ class Model(object):
             if pk_set:
                 # Determine whether a record with the primary key already exists.
                 if (force_update or (not force_insert and
-                        manager.filter(pk=pk_val).extra(select={'a': 1}).values('a').order_by())):
+                        manager.filter(pk=pk_val).exists())):
                     # It does already exist, so do an UPDATE.
                     if force_update or non_pks:
                         values = [(f, None, (raw and getattr(self, f.attname) or f.pre_save(self, False))) for f in non_pks]