Question

我在db中为此字段保存新值后，尝试显示db模型字段（RelatedModel.new_reply）的旧值。这应该起作用的方式是new_reply字段将回复（通过将其设置为1）标记为收件人（rto）未读。收件人查看邮件后，new_reply将重置为0.模板my_view.html会向收件人显示一个标记，如果他们有一个尚未点击查看的新回复。收件人第一次查看回复时，标记new_reply将被重置，后续视图不会被标记为新文件。

问题是除了存储在db中的值之外，行response.save()似乎也会更改new_reply中d的值。因此，my_view.html永远不会看到new_reply==1，只会看到new_reply==0。这对我来说似乎很奇怪，因为d一旦分配就应该独立于db。

为什么会发生这种情况以及如何解决这个问题？

class ParentModel (models.Model):
    msg = models.TextField()
    author = models.ForeignKey(User)

class RelatedModel (models.Model):
    msg = models.ForeignKey(ParentModel)
    reply = models.TextField()
    rto = models.ForeignKey(User, related_name='rto')
    new_reply = models.IntegerField(null=True, blank=True)

def view_msg(request, msg_id):
    m = get_object_or_404(ParentModel, pk=id)
    r = m.RelatedModel_set.all()
    d = add_csrf(request, m=m, r=r) # d.r.new_reply==1 should be rendered
    # Once the view data is ready for rendering, clear the new_reply
    # bit.  If we do it earlier, we will not be able to mark replies as new.
    if request.user.is_authenticated():
        for response in r:
            # Clear bit if current user is viewing reply addressed to them
            if (request.user == RelatedModel.rto):
                if response.new_reply == 1: # Is it a new reply?
                    response.new_reply = 0 # Reset the new_activity bits
                    response.save()
    return render_to_response('my_view.html',
                              {'db_data': d},
                              context_instance = RequestContext(request),
    )

Queryset评估序列。新活动位被意外覆盖

0 个答案: