外部キーを逆順に反復する

Question

私はDjangoのチュートリアルで書籍を使って地元の図書館のウェブサイトを作ろうとしています。 課題の1つは、作成者が作成したすべての書籍を一覧表示する著者詳細ビューを作成することです。著者の書籍情報を表示するのに問題があります。

Model.py

# -*- coding: utf-8 -*- 
from __future__ import unicode_literals 

from django.db import models 
from django.urls import reverse 
import uuid 

# Create your models here. 

class Genre(models.Model): 
    """ 
     Model resprenting the book genre 
    """ 
    name=models.CharField(max_length=200, help_text="Enter a book genre") 
    def __str__(self): 
     return self.name 

class Book(models.Model): 
    title = models.CharField(max_length=200) 
    author = models.ForeignKey('Author', on_delete=models.SET_NULL, null=True) 
    summary = models.TextField(max_length=1000, help_text="Enter a brief description") 
    isbn = models.CharField('ISBN', max_length=13, help_text="13 character ISBN field") 
    genre = models.ManyToManyField(Genre, help_text="Select a genre for this book") 

    def __str__(self): 
     return self.title 
    def get_absolute_url(self): 
     return reverse('book-detail', args=[str(self.id)]) 

    def display_genre(self): 
     return ', '.join([genre.name for genre in self.genre.all()[:3] ]) 

    display_genre.short_description = 'Genre' 


class BookInstance(models.Model): 
    id = models.UUIDField(primary_key=True, default=uuid.uuid4, help_text="Unique book number") 
    book = models.ForeignKey('Book', on_delete=models.SET_NULL, null=True) 
    imprint = models.CharField(max_length=200) 
    due_back = models.DateField(null=True, blank=True) 

    LOAN_STATUS = (
      ('d', 'Maintenance'), 
      ('o', 'On loan'), 
      ('a', 'Available'), 
      ('r', 'Reserved'), 
     ) 

    status = models.CharField(max_length=1, choices=LOAN_STATUS, blank=True, default='d', help_text="Book Availability") 

    class Meta: 
     ordering = ['due_back'] 

    def __str__(self): 
     return ('%s (%s)' %(self.id, self.book.title)) 

class Author(models.Model): 
    first_name = models.CharField(max_length=100) 
    last_name = models.CharField(max_length=100) 
    date_of_birth = models.CharField(max_length=10, null=True, blank=True) 
    date_of_death = models.CharField(max_length=10, null=True, blank=True) 

    def get_absolute_url(self): 
     return reverse('author-detail', args=[str(self.id)]) 
    def __str__(self): 
     return ('%s, %s' % (self.last_name, self.first_name)) 

    def display_books(self): 
     books = Book.objects.get(pk=self.id) 
     return books.book_set.all() 

    display_books.short_description = 'Books' 

author_detail.html

本当にここに失いました！

{% extends "base.html" %} 

{% block content %} 
<h1>Author: {{ author }}</h1> 
    <p><strong>Date of Birth:</strong> {{ author.date_of_birth }}</p> 
    <p><strong>Date of Death:</strong> {{ author.date_of_death }}</p> 
    <!--<p><strong>Books:</strong> {% for books in book.author.pk.all %} {{ book.author }}{% if not forloop.last %}, {% endif %}{% endfor %}</p> --> 


    <div style="margin-left:20px;margin-top:20px"> 
    <h4>Books</h4> 
    {% for books in book.all %} 
    <p>{{ books }} Testing Vars {{ book.author_set }} Get copies from key {{ book.author.pk }} </p> 
    {% endfor %} 
    </div> 
    {% endblock %} 

Views.py

# -*- coding: utf-8 -*- 
from __future__ import unicode_literals 

from django.shortcuts import render 
from django.views import generic 

# Create your views here. 

from .models import Book, Author, BookInstance, Genre 

def index(request): 
    num_books=Book.objects.all().count() 
    num_instances=BookInstance.objects.all().count() 
    #available books 
    num_instances_available=BookInstance.objects.filter(status__exact='a').count() 
    num_authors=Author.objects.count() 

    return render(request, 
     'index.html', 
     context={'num_books': num_books, 'num_instances': num_instances, 
      'num_instances_available' : num_instances_available, 'num_authors': num_authors}, 
    ) 

class BookListView(generic.ListView): 
    model = Book 

class BookDetailView(generic.DetailView): 
    model = Book 


class AuthorListView(generic.ListView): 
    model = Author 

class AuthorDetailView(generic.DetailView): 
    model = Author 

Answer 1

author_detail.htmlがAuthorDetailViewリストビューで使用されていると仮定すると、私はあなたの避難所、ので、多分このように、

{% block content %} 
<h1>Author: {{ object.first_name }} {{ object.last_name }}</h1> 
    <p><strong>Date of Birth:</strong> {{ object.date_of_birth }}</p> 
    <p><strong>Date of Death:</strong> {{ object.date_of_death }}</p> 

    <div style="margin-left:20px;margin-top:20px"> 
    <h4>Books</h4> 
    {% for book in object.book_set.all %} 
    <p>{{ book.title }}</p> 
    {% endfor %} 
    </div> 
    {% endblock %} 

をテンプレートでいくつかの変更をお勧めしたいですListViewのget_context_data()メソッドをオーバーライドしないと、デフォルトのcontext_variable_nameはobjectになります。 インスタンスをobjectで参照する必要があります。