Question

I have this model class:

class question(models.Model):
    id = models.CharField(max_length=64, primary_key=True,null=False)
    paper_id = models.ForeignKey(paper,null=True)
    question_no = models.SmallIntegerField('question_no',max_length=6,null=True)
    content = models.TextField('content',null=False)
    topic_id = models.ForeignKey(topic,null=True)
    subtopic_id = models.ForeignKey(subtopic,null=True)
    std_answer = models.CharField(max_length=128,null=True)
    marks = models.IntegerField('marks',max_length=2,null=True)
    input = models.CharField(max_length=512,null=True,default=None)
    type_answer = models.CharField(max_length=512,null=True)
    type = models.CharField(max_length=512,null=True,default=None)

    def __str__(self):
        return str(self.id)

I need to list all its attributes, inclusive of Topic.Title, Subtopic.Title, and Paper.Title which resides in foreign objects Topic, Subtopic, Paper respectively. How may I do so in a single query?

Answer 1

Your models.py must be like this for example:

class Topic(models.Model):
    .....

class SubTopic(models.Model)
    topic = models.ForeignKey(Topic)
    .....

class question(models.Model):
   question_no = models.SmallIntegerField('question_no',max_length=6,null=True)
   content = models.TextField('content',null=False)
   subtopic = models.ForeignKey(Subtopic)
   .....

You don’t have to put id because django will create it for you.

views.py

def page(request):
return render(request, 'page.html', {
    'topics' : topic.objects.filter()
}

if you want to get by id

def page(request, id):
    topics = topic.objects.get(pk=id)
return render(request, 'page.html', {
    'topics' : topic
}

Your model class is incorrect. You don’t have to put many foreignkey. One foreignkey is OK.

{% for topic in topics %}
    {{topic.title}}

    {% for subtopic in topic.subtopics  %}
        {{subtopic.title}}

        {% for question in subtopic.questions %}
            ............
        {% endfor %} 
    {% endfor %}
{% endfor %}