从数据库中重新加载django对象

有没有可能从数据库刷新django对象的状态？ 我的意思是行为大致相当于：

new_self = self.__class__.objects.get(pk=self.pk) for each field of the record: setattr(self, field, getattr(new_self, field)) 

UPD：在跟踪器中发现重新打开/ wontfix战争： http ://code.djangoproject.com/ticket/901。 仍然不明白为什么维护者不喜欢这个。

Answer 1

从Django 1.8内置刷新对象。 链接到文档 。

 def test_update_result(self): obj = MyModel.objects.create(val=1) MyModel.objects.filter(pk=obj.pk).update(val=F('val') + 1) # At this point obj.val is still 1, but the value in the database # was updated to 2. The object's updated value needs to be reloaded # from the database. obj.refresh_from_db() self.assertEqual(obj.val, 2) 

Answer 2

我发现从数据库重新加载对象相对容易，就像这样：

 x = X.objects.get(id=x.id) 

Answer 3

参考@ grep的评论，不应该有可能做到：

 # Put this on your base model (or monkey patch it onto django's Model if that's your thing) def reload(self): new_self = self.__class__.objects.get(pk=self.pk) # You may want to clear out the old dict first or perform a selective merge self.__dict__.update(new_self.__dict__) # Use it like this bar.foo = foo assert bar.foo.pk is None foo.save() foo.reload() assert bar.foo is foo and bar.foo.pk is not None