Getting and displaying related objects in Django

Question

I know this is simple, but I can't get my head around how to join some models together to display in my template in Django. I have "groups" that can have several "contacts".

So far I've got:

class Group(models.Model):
    group_name = models.CharField()

class Contact(models.Model):
    contact_name = models.ForeignKey(Group)

In my view, at first I assumed that simply getting my groups would also get any attached contacts, however that doesn't appear to be happening as expected:

def get_queryset(self):
    groups = Group.objects.all()
    return groups

I was expecting to do something like this in my template:

{% for group in groups %}
    <h2>{{ group.group_name }}</h2>
    {% for c in group.contact %}
        <h3>{{ c.contact_name }}</h3>
    {% endfor %}
{% endfor %}

This isn't working - what am I doing wrong? What is the correct query in my view to make sure the contact(s) for each group is getting retrieved?

As stated in this part of the doc: docs.djangoproject.com/en/1.5/ref/models/relations — sebastibe
– sebastibe, Commented Oct 13, 2013 at 6:59
Thanks Burhan, the way I was reading the docs, I thought the .contact_set method was to be used in the view, I didn't even think to use it in the template like that. Appreciated :) — mrhigham
– mrhigham, Commented Oct 13, 2013 at 7:44

Guilherme David da Costa · Accepted Answer · 2013-10-13 07:24:31Z

8

Well, it looks like you've got some of your code from a different place so just so you can fully understand, you can do this in 2 different ways:

1) To access a related object of any kind, being a simple ForeignKey or ManyToMany you just need to go from the opposite model and use _set like this example:

class Group(models.Model):
    group_name = models.CharField()

class Contact(models.Model):
    contact_name = models.ForeignKey(Group)

{{ group.contact_set.all }}

2) You can set up a name different than the default _set changing Contact like this:

class Contact(models.Model):
    contact_name = models.ForeignKey(Group, related_name='contacts')

So, related_name kwarg set a new name for you instead of the _set one:

{{ group.contacts.all }}

I hope I manage to make it clearer about simple access on models related objects.

answered Oct 13, 2013 at 7:24

Guilherme David da Costa

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4 Comments

mrhigham Over a year ago

Awesome, thanks! I had read about the "_set" method, but didn't realise it was to be used in the template. I thought I must have to use it in the view before I started looking at the template...! Thanks for your great answer.

Guilherme David da Costa Over a year ago

Yes, you can use it anywhere to access the related object. No problem, I'm glad I could help. :)

kd12345 Over a year ago

Hi, i know is been a long time since you have answered this question. I am still new to django and i am facing the same problem i tried solution 1 in my models.py but i keep getting 'ForeignKey' object has no attribute contact_set

Guilherme David da Costa Over a year ago

It looks like you're already calling your foreign key object. Can you share your code here? Otherwise, try changing contact_set to all()

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