Django查詢多對一關係

Question

我有三種模式，一個主題可以有零個或多個問題，一個問題可以有零個或多個答案。只有一個答案是正確的。

他們是多對一的關係。

class Topic(models.Model): 

class Question(models.Model): 
    topic = models.ForeignKey(Topic) 

class Answer(models.Model): 
    question = models.ForeignKey(Question) 
    isright = models.BooleanField(verbose_name='Right') 

現在我試圖循環根據主題的問題，我怎樣才能實現它與模板？

<topic> 

    <question> 
    <answer> 
    <answer> 
    <answer> 
    <answer> 

    <question> 
    <answer> 
    <answer> 
    <answer> 
    <answer> 

如何爲問題添加分頁程序？

paginator = Paginator(topic.question_set.all(), 25) 

Answer 1

如果我已經瞭解好了，你要循環利用 '主題' 命令答案：

answers = Answer.objects.order_by('question__topic', 'question') 

或：

for topic in Topic.objects.all(): 
    for question in topic.question_set.all(): 
     for answer in question.answer_set.all(): 
      ...do something... 

在模板中，你可以做同樣的，提供變量topics as Topic.objects.all（）：

{% for topic in topics %} 
    {% for question in topic.question_set.all %} 
     {% for answer in question.answer_set.all %} 
      ...do something... 
     {% endfor %} 
    {% endfor %} 
{% endfor %} 

Answer 2

topic_instance.question_set.all() 

見docs

Answer 3

使用* _set.all（）變量：

t = Topic.objects.get(id=X) 
questions = t.question_set.all() 

for q in questions: 
    answers = q.answer_set.all() 

    for a in answers: 
      print a