django/tests/many_to_one_null/models.py

32 lines
750 B
Python
Raw Normal View History

"""
Many-to-one relationships that can be null
To define a many-to-one relationship that can have a null foreign key, use
``ForeignKey()`` with ``null=True`` .
"""
from django.db import models
class Reporter(models.Model):
name = models.CharField(max_length=30)
class Article(models.Model):
headline = models.CharField(max_length=100)
reporter = models.ForeignKey(Reporter, models.SET_NULL, null=True)
class Meta:
ordering = ('headline',)
def __str__(self):
return self.headline
2014-09-24 00:29:17 +08:00
class Car(models.Model):
make = models.CharField(max_length=100, null=True, unique=True)
class Driver(models.Model):
car = models.ForeignKey(Car, models.SET_NULL, to_field='make', null=True, related_name='drivers')