Django-如何从关系中获取数据？

Question

我试图通过多一到多的一对多关系获取数据。

view.py

class PublisherDetailView(generic.DetailView):
     model = Publisher
     template_name = 'store/publisher_detail_view.html'

models.py

class Publisher(models.Model):
    name = models.CharField(null=False, max_length=30)
    image = models.ImageField(upload_to='publisher_images/')
    
class Book(models.Model):
    title = models.CharField(null=False, max_length=30)
    description = models.CharField(max_length=1000)
    publisher = models.ForeignKey(Publisher, on_delete=models.CASCADE)
    
class reader(models.Model):
    name = models.CharField(max_length=40)
    book = models.ManyToManyField(Book)

publisher_detail_view.html

{% for reader in publisher.book_set.readers.all %}
    <p>{{ reader.name }} </p>
{% endfor %}

我只想从Specfic Publisher那里吸引所有读者。模板中正确的代码是什么？ Publisher.book_set.readers.all对我有意义（早期初学者），但不起作用

Answer 1

book_set.readers不起作用，因为book_set是管理书籍列表的经理。要吸引读者，您必须通过书籍进行迭代：

{% for book in publisher.book_set.all %}
    {% for reader in book.reader_set.all %}
        <p>{{ reader.name }} </p>
    {% endfor %}
{% endfor %}