CODEWITHSUNDEEP
djangopython-3.xdjango-viewsdjango-queryset
belonious
belonious

Reputation: 133

transform queryset to dict of dicts django

i am trying to make a dict of dicts with data and pass it to template.

models.py

 class Lesson(models.Model):
 ...

 class Files(models.Model):
 ...

 class Section(models.Model):
   file = models.ManyToManyField(Files)
   lesson = models.ForeignKey(Lesson)

views.py

def LessonView(request):
    the_data={}
    all_lessons= Lesson.objects.all()
    for lesson in all_lessons:
        the_data[lesson]=lesson.section_set.all()
        for section in the_data[lesson]:
            the_data[lesson][section]=section.file.all() <---error
    Context={
        'the_data':the_data,
        }
return render(request, 'TMS/lessons.html', Context)

i get an error:

 Exception Value:   

 'QuerySet' object does not support item assignment

i am new to django and programming so take it easy.is this the right way to pass the data so i can show a list of files for each section for each lesson,in the template?

Upvotes: 0

Views: 546

Answers (1)

Daniel Roseman
Daniel Roseman

Reputation: 599956

You don't need to convert to a dict of dicts to pass to the template. You can iterate through the queryset directly, and for each one you can get the related sections and files:

{% for lesson in all_lessons %}
    {{ lesson.name }}
    {% for section in lesson.section_set.all %}
        {{ section.name }}
        {% for file in section.file.all %}
            {{ file.name }}
        {% endfor %}
    {% endfor %}
{% endfor %}

Note that this (just like your original approach) is very expensive in terms of database queries: you should investigate using prefetch_related in the view to cut down on those.

Upvotes: 2

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