cannot acces foreign keys in django - django

Question

I have the following template:
{% extends "artdb/base.html" %}
{% block content1 %}
<h4>Persons:</h4>
<ul>
{% for p in ans %}
<h5>First name: {{p.firstName}}</h5>
<h5>Last name: {{p.lastName}}</h5>
<h5>Phone: {{p.phoneNumber}}</h5>
<h5>Adress: {{p.streetAdress}}</h5>
<h5>Zip Code: {{p.zipcode}}</h5>
<h5>City: {{p.city}}</h5>
<hr>
{% endfor %}
</ul>
{% endblock content1 %}
{% block content2 %}
<h4>Roles:</h4>
<ul>
{% for p in ans %}
<h5>Role:{{p.persons.role}}</h5>
<hr>
{% endfor %}
</ul>
{% endblock content2 %}
and the model:
class Person(models.Model):
mail=models.EmailField()
firstName=models.CharField(max_length=200)
lastName=models.CharField(max_length=200)
phoneNumber=PhoneNumberField()
streetAdress=models.CharField(max_length=200)
zipcode=models.CharField(max_length=200)
city=models.CharField(max_length=200,default="Göteborg")
country=models.CharField(max_length=200,default="Sweden")
def __str__(self):
return "%s %s" % (self.firstName,self.lastName)
class Meta:
ordering = ('firstName','lastName')
class Role(models.Model):
role=models.CharField(max_length=200)
person=models.ManyToManyField(Person)
def __str__(self):
return self.role
class Meta:
ordering = ('role',)
But when I run the above code the only output that I get is from the block content1, i.e I cannot access the role content. I thought that role.persons.role would do it but apperantley not. There is a many-to-many relationship between perssons and roles.
Any ideas?

Answer 1

This should work
{% block content2 %}
<h4>Roles:</h4>
<ul>
{% for p in ans %}
{% for role in p.role_set.all %}
<h5>Role:{{ role }}</h5>
<hr>
{% endfor %}
{% endfor %}
</ul>
{% endblock content2 %}
We have to create a second for loop, since a many to many relationship will always return a list. Not a single instance. So essentially it's just like accessing a 2d array.
In Django you only have to define a n:n relationship on one end. Django will then automatically add it to the other model as well. It does this by taking the related model name and suffixing _set. So if we want to reference all of the roles attached to a person, it would be person.role_set. The other way around it would be role.person like you defined in the model.