mirror of
https://github.com/django/django.git
synced 2024-11-19 07:54:07 +00:00
25264c8604
git-svn-id: http://code.djangoproject.com/svn/django/trunk@549 bcc190cf-cafb-0310-a4f2-bffc1f526a37
98 lines
2.8 KiB
Python
98 lines
2.8 KiB
Python
"""
|
|
4. Many-to-one relationships
|
|
|
|
To define a many-to-one relationship, use ``ForeignKey()`` .
|
|
"""
|
|
|
|
from django.core import meta
|
|
|
|
class Reporter(meta.Model):
|
|
first_name = meta.CharField(maxlength=30)
|
|
last_name = meta.CharField(maxlength=30)
|
|
|
|
def __repr__(self):
|
|
return "%s %s" % (self.first_name, self.last_name)
|
|
|
|
class Article(meta.Model):
|
|
headline = meta.CharField(maxlength=100)
|
|
pub_date = meta.DateField()
|
|
reporter = meta.ForeignKey(Reporter)
|
|
|
|
def __repr__(self):
|
|
return self.headline
|
|
|
|
API_TESTS = """
|
|
# Create a Reporter.
|
|
>>> r = reporters.Reporter(first_name='John', last_name='Smith')
|
|
>>> r.save()
|
|
|
|
# Create an Article.
|
|
>>> from datetime import datetime
|
|
>>> a = articles.Article(id=None, headline="This is a test", pub_date=datetime(2005, 7, 27), reporter=r)
|
|
>>> a.save()
|
|
|
|
>>> a.reporter_id
|
|
1
|
|
|
|
>>> a.get_reporter()
|
|
John Smith
|
|
|
|
# Article objects have access to their related Reporter objects.
|
|
>>> r = a.get_reporter()
|
|
>>> r.first_name, r.last_name
|
|
('John', 'Smith')
|
|
|
|
# Create an Article via the Reporter object.
|
|
>>> new_article = r.add_article(headline="John's second story", pub_date=datetime(2005, 7, 29))
|
|
>>> new_article
|
|
John's second story
|
|
>>> new_article.reporter_id
|
|
1
|
|
|
|
# Reporter objects have access to their related Article objects.
|
|
>>> r.get_article_list(order_by=['pub_date'])
|
|
[This is a test, John's second story]
|
|
|
|
>>> r.get_article(headline__startswith='This')
|
|
This is a test
|
|
|
|
>>> r.get_article_count()
|
|
2
|
|
|
|
# The API automatically follows relationships as far as you need.
|
|
# Use double underscores to separate relationships.
|
|
# This works as many levels deep as you want. There's no limit.
|
|
# Find all Articles for any Reporter whose first name is "John".
|
|
>>> articles.get_list(reporter__first_name__exact='John', order_by=['pub_date'])
|
|
[This is a test, John's second story]
|
|
|
|
# Find all Articles for the Reporter whose ID is 1.
|
|
>>> articles.get_list(reporter__id__exact=1, order_by=['pub_date'])
|
|
[This is a test, John's second story]
|
|
|
|
# Note you need two underscores between "reporter" and "id" -- not one.
|
|
>>> articles.get_list(reporter_id__exact=1)
|
|
Traceback (most recent call last):
|
|
...
|
|
TypeError: got unexpected keyword argument 'reporter_id__exact'
|
|
|
|
# "pk" shortcut syntax works in a related context, too.
|
|
>>> articles.get_list(reporter__pk=1, order_by=['pub_date'])
|
|
[This is a test, John's second story]
|
|
|
|
# You can also instantiate an Article by passing
|
|
# the Reporter's ID instead of a Reporter object.
|
|
>>> a3 = articles.Article(id=None, headline="This is a test", pub_date=datetime(2005, 7, 27), reporter_id=r.id)
|
|
>>> a3.save()
|
|
>>> a3.reporter_id
|
|
1
|
|
>>> a3.get_reporter()
|
|
John Smith
|
|
|
|
# Similarly, the reporter ID can be a string.
|
|
>>> a4 = articles.Article(id=None, headline="This is a test", pub_date=datetime(2005, 7, 27), reporter_id="1")
|
|
>>> a4.save()
|
|
>>> a4.get_reporter()
|
|
John Smith
|
|
"""
|