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git-svn-id: http://code.djangoproject.com/svn/django/trunk@1315 bcc190cf-cafb-0310-a4f2-bffc1f526a37
99 lines
2.8 KiB
Python
99 lines
2.8 KiB
Python
"""
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4. Many-to-one relationships
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To define a many-to-one relationship, use ``ForeignKey()`` .
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"""
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from django.core import meta
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class Reporter(meta.Model):
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first_name = meta.CharField(maxlength=30)
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last_name = meta.CharField(maxlength=30)
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email = meta.EmailField()
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def __repr__(self):
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return "%s %s" % (self.first_name, self.last_name)
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class Article(meta.Model):
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headline = meta.CharField(maxlength=100)
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pub_date = meta.DateField()
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reporter = meta.ForeignKey(Reporter)
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def __repr__(self):
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return self.headline
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API_TESTS = """
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# Create a Reporter.
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>>> r = reporters.Reporter(first_name='John', last_name='Smith', email='john@example.com')
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>>> r.save()
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# Create an Article.
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>>> from datetime import datetime
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>>> a = articles.Article(id=None, headline="This is a test", pub_date=datetime(2005, 7, 27), reporter=r)
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>>> a.save()
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>>> a.reporter_id
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1
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>>> a.get_reporter()
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John Smith
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# Article objects have access to their related Reporter objects.
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>>> r = a.get_reporter()
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>>> r.first_name, r.last_name
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('John', 'Smith')
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# Create an Article via the Reporter object.
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>>> new_article = r.add_article(headline="John's second story", pub_date=datetime(2005, 7, 29))
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>>> new_article
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John's second story
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>>> new_article.reporter_id
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1
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# Reporter objects have access to their related Article objects.
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>>> r.get_article_list(order_by=['pub_date'])
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[This is a test, John's second story]
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>>> r.get_article(headline__startswith='This')
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This is a test
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>>> r.get_article_count()
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2
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# The API automatically follows relationships as far as you need.
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# Use double underscores to separate relationships.
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# This works as many levels deep as you want. There's no limit.
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# Find all Articles for any Reporter whose first name is "John".
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>>> articles.get_list(reporter__first_name__exact='John', order_by=['pub_date'])
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[This is a test, John's second story]
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# Find all Articles for the Reporter whose ID is 1.
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>>> articles.get_list(reporter__id__exact=1, order_by=['pub_date'])
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[This is a test, John's second story]
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# Note you need two underscores between "reporter" and "id" -- not one.
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>>> articles.get_list(reporter_id__exact=1)
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Traceback (most recent call last):
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...
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TypeError: got unexpected keyword argument 'reporter_id__exact'
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# "pk" shortcut syntax works in a related context, too.
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>>> articles.get_list(reporter__pk=1, order_by=['pub_date'])
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[This is a test, John's second story]
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# You can also instantiate an Article by passing
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# the Reporter's ID instead of a Reporter object.
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>>> a3 = articles.Article(id=None, headline="This is a test", pub_date=datetime(2005, 7, 27), reporter_id=r.id)
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>>> a3.save()
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>>> a3.reporter_id
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1
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>>> a3.get_reporter()
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John Smith
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# Similarly, the reporter ID can be a string.
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>>> a4 = articles.Article(id=None, headline="This is a test", pub_date=datetime(2005, 7, 27), reporter_id="1")
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>>> a4.save()
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>>> a4.get_reporter()
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John Smith
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"""
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