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git-svn-id: http://code.djangoproject.com/svn/django/trunk@614 bcc190cf-cafb-0310-a4f2-bffc1f526a37
64 lines
2.1 KiB
Python
64 lines
2.1 KiB
Python
"""
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6. Specifying ordering
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Specify default ordering for a model using the ``ordering`` attribute, which
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should be a list or tuple of field names. This tells Django how to order the
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results of ``get_list()`` and other similar functions.
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If a field name in ``ordering`` starts with a hyphen, that field will be
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ordered in descending order. Otherwise, it'll be ordered in ascending order.
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The special-case field name ``"?"`` specifies random order.
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The ordering attribute is not required. If you leave it off, ordering will be
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undefined -- not random, just undefined.
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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(headline='Article 1', pub_date=datetime(2005, 7, 26))
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>>> a1.save()
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>>> a2 = articles.Article(headline='Article 2', pub_date=datetime(2005, 7, 27))
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>>> a2.save()
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>>> a3 = articles.Article(headline='Article 3', pub_date=datetime(2005, 7, 27))
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>>> a3.save()
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>>> a4 = articles.Article(headline='Article 4', pub_date=datetime(2005, 7, 28))
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>>> a4.save()
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# By default, articles.get_list() orders by pub_date descending, then
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# headline ascending.
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>>> articles.get_list()
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[Article 4, Article 2, Article 3, Article 1]
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# Override ordering with order_by, which is in the same format as the ordering
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# attribute in models.
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>>> articles.get_list(order_by=['headline'])
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[Article 1, Article 2, Article 3, Article 4]
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>>> articles.get_list(order_by=['pub_date', '-headline'])
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[Article 1, Article 3, Article 2, Article 4]
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# Use the "limit" parameter to limit the results.
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>>> articles.get_list(order_by=['headline'], limit=2)
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[Article 1, Article 2]
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# Use the "offset" parameter with "limit" to offset the result list.
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>>> articles.get_list(order_by=['headline'], offset=1, limit=2)
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[Article 2, Article 3]
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# Use '?' to order randomly. (We're using [...] in the output to indicate we
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# don't know what order the output will be in.
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>>> articles.get_list(order_by=['?'])
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[...]
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"""
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