Question

我知道这个问题似乎已经回答了好几次，但是我发现的任何答案都没有给我任何指向我所面临问题的指针。

我在Django应用程序中有3种模型：

class Person(models.Model):
  name = model.CharField(...)

class Topic(models.Model):
  key = model.CharField(...)

class Interest(models.Model):
  person = models.ForeignKey(Person, on_delete=models.CASCADE)
  topic = models.ForeignKey(Topic, on_delete=models.CASCADE)
  comment = models.CharField(...)

Person.interests = models.ManyToManyField(Topic, through="Interest")

views.py声明如下：

class IndexView(generic.ListView):
  template_name = 'index.html'
  context_object_name = 'people_list'

  def get_queryset(self):
    return Person.objects.all()

index.html如下所示：

    {% for person in people_list %}
        <tr>
            <td>{{ person.name }}</td>
            <td>
                <ul>
                {% for interest in person.interests.all %}
                    <li>{{ interest }}</li>
                {% empty %}
                    No interest found
                {% endfor %}
                </ul>
            </td>
        </tr>
    {% endfor %}

令人惊讶的是，当管理站点清楚地显示了所有人的兴趣时，该视图将为每个人返回“未发现兴趣”。

Person.objects.all()中的views.py似乎没有从数据库中加载相关对象。

使用外壳时，我得到以下结果：

Python 3.7.2 (default, Feb 12 2019, 08:15:36)
[Clang 10.0.0 (clang-1000.11.45.5)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
(InteractiveConsole)
>>> from app.models import Person, Topic, Interest
>>> person = Person.objects.all()[0]
>>> person.interests
<django.db.models.fields.related.ManyToManyField>
>>> person.interests.all()
Traceback (most recent call last):
  File "<console>", line 1, in <module>
AttributeError: 'ManyToManyField' object has no attribute 'all'

Answer 1

您必须在类定义中定义字段。这应该起作用：

class Person(models.Model):
    name = model.CharField(...)
    interests = models.ManyToManyField('Topic', through='Interest')

通过多对多枚举相关对象

1 个答案: