如何解决 Django IntegrityError NOT NULL 约束字段？

Question

我正在构建一个在线法官，其中我有一个问题模型和一个答案模型。

models.py

from django.db import models
from django.core.validators import FileExtensionValidator
from django.urls import reverse

class Question(models.Model):
    title = models.CharField(max_length=100)
    content = models.TextField()
    solution = models.FileField(
    validators=[FileExtensionValidator(allowed_extensions=['txt'])], upload_to= 'media')

    def __str__(self):
        return self.title

    def get_absolute_url(self):
        return reverse('coder:detail', kwargs={'pk': self.pk})

class Answer(models.Model):
    question = models.ForeignKey(Question, on_delete=models.CASCADE)
    result = models.CharField(max_length=100,default = 'answer', null = True, blank = True)
    # result = models.FileField( null= True, blank=True, default = 'media/media/output.txt',
    # validators=[FileExtensionValidator(allowed_extensions=['txt'])], upload_to= 'media')

    def __str__(self):
        return f'{self.question.title} Answer'
    def get_absolute_url(self):
        return reverse('coder:detail', kwargs={'pk': self.pk})

views.py

from django.shortcuts import get_object_or_404, render
from django.urls import reverse_lazy
from django.contrib.auth.mixins import LoginRequiredMixin, UserPassesTestMixin
from django.views.generic import ListView, DetailView, CreateView, UpdateView, RedirectView
from django.db.models import Q
from .models import Question, Answer


class CoderListView(ListView):
    model = Question
    template_name = "coder/coder_list.html"
    context_object_name = 'question'


class CoderDetailView(DetailView):
    model = Question
    template_name = "coder/coder_detail.html"


class CoderCreateView(CreateView):
    model = Answer
    fields = ['result']
    context_object_name = 'answer'
    success_url = reverse_lazy('coder:list')
    template_name = "coder/coder_form.html"

    def form_valid(self, form):
        return super().form_valid(form)

我到底做错了什么？

我之前尝试过 FileField，但是当我不断收到错误时，我在刷新数据库后尝试了 CharField 以进一步调试，但我一直收到此错误：

是的，我确实尝试过适当地设置 null、空白和默认值，但仍然没有运气。也许与signals.py 文件有关？或者，也许我正在错误地执行外键，无论我做错了什么，我现在都无法指出。我们将不胜感激。

此页面正在使用 CoderCreateView。

Answer 1

我相信这是导致问题的原因：

class CoderCreateView(CreateView):
    model = Answer
    fields = ['result']
    context_object_name = 'answer'

对于答案模型，您忘记传递答案所链接的问题的主键/对象（无论您喜欢哪种方式），如models.py 中的这一行：

question = models.ForeignKey(Question, on_delete=models.CASCADE)