88 lines
2.7 KiB
Python
88 lines
2.7 KiB
Python
"""
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7. The lookup API
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This demonstrates features of the database API.
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"""
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from django.core import meta
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class Article(meta.Model):
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headline = meta.CharField(maxlength=100)
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pub_date = meta.DateTimeField()
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class META:
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ordering = ('-pub_date', 'headline')
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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 couple of Articles.
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>>> from datetime import datetime
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>>> a1 = articles.Article(id=None, headline='Article 1', pub_date=datetime(2005, 7, 26))
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>>> a1.save()
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>>> a2 = articles.Article(id=None, headline='Article 2', pub_date=datetime(2005, 7, 27))
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>>> a2.save()
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>>> a3 = articles.Article(id=None, headline='Article 3', pub_date=datetime(2005, 7, 27))
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>>> a3.save()
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>>> a4 = articles.Article(id=None, headline='Article 4', pub_date=datetime(2005, 7, 28))
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>>> a4.save()
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# get_iterator() is just like get_list(), but it's a generator.
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>>> for a in articles.get_iterator():
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... print a.headline
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Article 4
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Article 2
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Article 3
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Article 1
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# get_iterator() takes the same lookup arguments as get_list().
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>>> for a in articles.get_iterator(headline__endswith='4'):
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... print a.headline
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Article 4
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# get_count() returns the number of objects matching search criteria.
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>>> articles.get_count()
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4L
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>>> articles.get_count(pub_date__exact=datetime(2005, 7, 27))
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2L
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>>> articles.get_count(headline__startswith='Blah blah')
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0L
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# get_in_bulk() takes a list of IDs and returns a dictionary mapping IDs
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# to objects.
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>>> articles.get_in_bulk([1, 2])
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{1: Article 1, 2: Article 2}
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>>> articles.get_in_bulk([3])
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{3: Article 3}
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>>> articles.get_in_bulk([1000])
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{}
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# get_values() is just like get_list(), except it returns a list of
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# dictionaries instead of object instances -- and you can specify which fields
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# you want to retrieve.
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>>> articles.get_values(fields=['headline'])
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[{'headline': 'Article 4'}, {'headline': 'Article 2'}, {'headline': 'Article 3'}, {'headline': 'Article 1'}]
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>>> articles.get_values(pub_date__exact=datetime(2005, 7, 27), fields=['id'])
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[{'id': 2}, {'id': 3}]
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>>> articles.get_values(fields=['id', 'headline']) == [{'id': 4, 'headline': 'Article 4'}, {'id': 2, 'headline': 'Article 2'}, {'id': 3, 'headline': 'Article 3'}, {'id': 1, 'headline': 'Article 1'}]
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True
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# get_values_iterator() is just like get_values(), but it's a generator.
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>>> for d in articles.get_values_iterator(fields=['id', 'headline']):
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... i = d.items()
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... i.sort()
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... i
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[('headline', 'Article 4'), ('id', 4)]
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[('headline', 'Article 2'), ('id', 2)]
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[('headline', 'Article 3'), ('id', 3)]
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[('headline', 'Article 1'), ('id', 1)]
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# Every DateField and DateTimeField creates get_next_by_FOO() and
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# get_previous_by_FOO() methods.
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>>> a3.get_next_by_pub_date()
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Article 4
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>>> a2.get_previous_by_pub_date()
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Article 1
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"""
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