Solved

Querying database objects based on foreign key in Django

Posted on 2014-11-23
2
179 Views
Last Modified: 2014-11-25
Hello,

I'm relatively new to Django, and I'm trying to modify the Django tutorial (https://docs.djangoproject.com/en/1.7/intro/tutorial04/)a little bit.

What I'm trying to do is get the votes and the questions on the same page.

Now, I know that I can get dictionaries to work; because I got this to work:

def index(request):
    latest_question_list = Question.objects.order_by('-pub_date')[:5]

    question_dictionary = {}

    question_dictionary[latest_question_list[0]] = ['test', 'a', 'b', 'c']

    context = {'question_dictionary': question_dictionary}
    return render(request, 'quizzes/index.html', context)

index.html:
% if question_dictionary %}
        {% for question, choices in question_dictionary.items %}
        <p>{{ question }}</p>
            <ul>
            {% for choice in choices %}
                <input type="radio" name="choice" id="choice {{ forloop.counter }}" value="{{ choice.id }}" />
                <label for="choice {{ forloop.counter }}">{{ choice }}</label><br />
            {% endfor %}
            </ul>
        {% endfor %}
{% else %}
        <p>No questions are available.</p>
{% endif %}

Open in new window


But the following code doesn't work; is there some simple thing in Django I'm missing?

views.py:
def index(request):
    latest_question_list = Question.objects.order_by('-pub_date')

    question_dictionary = {}

    for question in latest_question_list:
        question_dictionary[question.question_text] = question_dictionary.get(question.question_text, [])
        if not question_dictionary[question.question_text]:
            temp_list = get_object_or_404(question.question_text, pk=question.pk)
            question_dictionary[question.question_text] = temp_list

index.html:
{% if question_dictionary %}
        {% for question, choices in question_dictionary.items %}
        <p>{{ question }}</p>
            <ul>
            {% for choice in choices %}
                <input type="radio" name="choice" id="choice {{ forloop.counter }}" value="{{ choice.id }}" />
                <label for="choice {{ forloop.counter }}">{{ choice.choice_text }}</label><br />
            {% endfor %}
            </ul>
        {% endfor %}
{% else %}
        <p>No questions are available.</p>
{% endif %}

Open in new window


Appreciate any help!
0
Comment
Question by:Errang Genevre
2 Comments
 
LVL 25

Accepted Solution

by:
clockwatcher earned 500 total points
ID: 40461526
The choices for a question are retrieved through a question's choice_set property.

There's really no reason to pass in a dictionary.  You'd typically do something more like this:
views.py
def index(request):
    latest_question_list = Question.objects.order_by('-pub_date')[:5]
    return render(request, 'polls/index.html', {'latest_question_list': latest_question_list })

Open in new window

index.html
{% if latest_question_list %}
	{% for question in latest_question_list %}
        <p>{{ question }}</p>
            <ul>
            {% for choice in question.choice_set.all %}
                <input type="radio" name="choice" id="choice {{ forloop.counter }}" value="{{ choice.id }}" />
                <label for="choice {{ forloop.counter }}">{{ choice.choice_text }}</label><br />
            {% endfor %}
            </ul>
        {% endfor %}
{% else %}
        <p>No questions are available.</p>
{% endif %}

Open in new window


But if you want it in a dictionary that works with your posted template, then:
views.py
def index(request):
    latest_question_list = Question.objects.order_by('-pub_date')[:5]
    question_dictionary = dict([ (q, q.choice_set.all()) for q in latest_question_list ])
    return render(request, 'polls/index.html', {'question_dictionary': question_dictionary })

Open in new window

0
 

Author Closing Comment

by:Errang Genevre
ID: 40466030
Thanks a lot!
0

Featured Post

Free camera licenses with purchase of My Cloud NAS

Milestone Arcus software is compatible with thousands of industry-leading cameras for added flexibility. Upon installation on your My Cloud NAS, you will receive two (2) camera licenses already enabled in the software. And for a limited time, get additional camera licenses FREE.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

This article will show the steps for installing Python on Ubuntu Operating System. I have created a virtual machine with Ubuntu Operating system 8.10 and this installing process also works with upgraded version of Ubuntu OS. For installing Py…
When we want to run, execute or repeat a statement multiple times, a loop is necessary. This article covers the two types of loops in Python: the while loop and the for loop.
The viewer will learn how to dynamically set the form action using jQuery.
This tutorial will teach you the core code needed to finalize the addition of a watermark to your image. The viewer will use a small PHP class to learn and create a watermark.

863 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

20 Experts available now in Live!

Get 1:1 Help Now