Question

我对django很新，我无法理解为什么会出现这个错误： project_question_text.question_id may not be NULL 我有相互连接的模型和视图：

class Question_Text(models.Model):
    text_en = models.CharField(max_length=60, blank=True)


class Question(models.Model):
    user = models.ForeignKey(User)
    question_text = models.ForeignKey(Question_Text)
    viewed = models.BooleanField(default=False)
    def __unicode__(self):
        return self.question_text

并查看：

def add_question(request, project_id):
    a = Project.objects.get(id=project_id)
    if request.method == "POST":
        f = QuestionForm(request.POST)
        if f.is_valid():
            c = f.save(commit=False)
            c.project = a
            c.save()

            messages.success(request, "Your question was added")

            return HttpResponseRedirect('/projects/get/%s' % project_id)

    else:
        f = QuestionForm()

    args = {}
    args.update(csrf(request))

    args['project'] = a
    args['form'] = f

    return render_to_response('project/add_question.html', args)

请问有人建议吗？

Answer 1

您确定是否使用请求参数在else条件下初始化新对象？

def add_question(request, project_id):
a = Project.objects.get(id=project_id)
if request.method == "POST":
f = QuestionForm(request.POST)
if f.is_valid():
    c = f.save(commit=False)
    c.project = a
    c.save()

    messages.success(request, "Your question was added")

    return HttpResponseRedirect('/projects/get/%s' % project_id)

else:
    f = QuestionForm(request.POST) #Add request params to initialization 

args = {}
args.update(csrf(request))

args['project'] = a
args['form'] = f

return render_to_response('project/add_question.html', args)

Answer 2

错误消息似乎表明question_id表中有project_question_text列，但Question_Text模型不包含Question的任何ForeignKey。我的猜测是，您曾经在question = models.ForeignKey(Question)模型中使用Question_Text这样的字段，并且在某些时候您更改了模型定义。您的数据库表仍会反映旧模式，而模型则不会。

最简单的解决方案是删除您已更改的所有表并再次运行syncdb。另一种解决方案是使用迁移（即South）。

^{一个稍微偏离主题的旁注，标准Python代码样式建议使用CamelCase而不使用下划线来表示类名，这意味着Question_Text模型的名称会更好，更标准{{1} }。}

如何在处理另一个模型时创建模型？

2 个答案: