django/tests/modeltests/reverse_lookup/models.py

"""
25. Reverse lookups

This demonstrates the reverse lookup features of the database API.
"""

from django.db import models

class User(models.Model):
    name = models.CharField(max_length=200)

    def __unicode__(self):
        return self.name

class Poll(models.Model):
    question = models.CharField(max_length=200)
    creator = models.ForeignKey(User)

    def __unicode__(self):
        return self.question

class Choice(models.Model):
    name = models.CharField(max_length=100)
    poll = models.ForeignKey(Poll, related_name="poll_choice")
    related_poll = models.ForeignKey(Poll, related_name="related_choice")

    def __unicode__(self):
        return self.name