After refresh page results are change for dictsort() in django template

Question

structure of model is i am using hvad for multilingual

class Course(TranslatableModel):

    translations = TranslatedFields(
        domain = models.ForeignKey('domain.Domain'),
        #track = models.ForeignKey('track.Track'),
        track = models.ForeignKey('track.Track', blank=True, null=True),
        course_nm = models.CharField(max_length=100, verbose_name =_('Course Name')),
        nature_of_training = models.TextField(verbose_name = _('Nature of Training')),
        duration = models.PositiveIntegerField(verbose_name =_('Duration')),
        sem = models.PositiveIntegerField(verbose_name =_('Semester')),
        degree_level = models.CharField(max_length=100, verbose_name =_('Degree Level')),
        credit = models.PositiveIntegerField(verbose_name =_('Credits')),
        locations = models.CharField(max_length=100, verbose_name =_('Locations')),
        accessible = models.CharField(max_length=100, verbose_name =_('Accessible')),
        des = models.TextField(verbose_name = _('Description')),
        admission_details = models.TextField(verbose_name = _('Admission Details')),
        further_study_details = models.TextField(verbose_name = _('Further Study Details')),
        seats = models.PositiveIntegerField(verbose_name =_('Seats')),
        title = models.CharField(max_length=512, verbose_name=_('Title')),
        slug = models.SlugField(max_length=512, verbose_name=_('Slug')),
        created_date = models.DateTimeField(auto_now_add=True, blank=True, null=True),
        updated_date = models.DateTimeField(auto_now=True, blank=True, null=True),
        created_by = models.ForeignKey(User, blank=True, null=True, editable=False),



    )

pass object in context from view to template for sorting i apply this,

in views.py i simply pass objects in context

def get_context_data(self, **kwargs):

     context = super(DegreeDetailView, self).get_context_data(**kwargs)

     context['courses'] = Course.objects.all()

return context

in template

                 {% for c in courses|dictsort:"track" %}

                    {% if c.domain|stringformat:"s" == d.domain_nm %}

                        {% if c.track != None %}
                            <h3>{{ c.track }}</h3>
                        {% endif %}

                      {{ c.course_nm }}

                    {% endif %}

                {% endfor %}

But After refresh page each time results are change,

so what i should do for sorting in django template,or any alternative is possible for sorting in django template I try a lot but not find solution,

Thanks in Advance!!

Answer 1

I think, that the reason, why you get different results, is because track can be null:

track = models.ForeignKey('track.Track', blank=True, null=True),

So, courses with track field set to null will not have exact order, and therefore they will be rendered in random positions. So, either you need all track fields to be set to some value (and probably remove blank=True, null=True + apply migrations), either sort by another field.

Also, sorting models using dictsort in templates is not the best way to do. Better do it at database level, providing order_by to you queryset:

context['courses'] = Course.objects.all().order_by('track__id')