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Migrated select_related doctests. Thanks to Eric Florenzano.
git-svn-id: http://code.djangoproject.com/svn/django/trunk@13828 bcc190cf-cafb-0310-a4f2-bffc1f526a37
This commit is contained in:
Russell Keith-Magee
@@ -56,134 +56,4 @@ class Species(models.Model):
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name = models.CharField(max_length=50)
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genus = models.ForeignKey(Genus)
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def __unicode__(self):
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return self.name
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def create_tree(stringtree):
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"""Helper to create a complete tree"""
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names = stringtree.split()
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models = [Domain, Kingdom, Phylum, Klass, Order, Family, Genus, Species]
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assert len(names) == len(models), (names, models)
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parent = None
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for name, model in zip(names, models):
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try:
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obj = model.objects.get(name=name)
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except model.DoesNotExist:
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obj = model(name=name)
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if parent:
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setattr(obj, parent.__class__.__name__.lower(), parent)
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obj.save()
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parent = obj
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__test__ = {'API_TESTS':"""
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# Set up.
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# The test runner sets settings.DEBUG to False, but we want to gather queries
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# so we'll set it to True here and reset it at the end of the test suite.
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>>> from django.conf import settings
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>>> settings.DEBUG = True
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>>> create_tree("Eukaryota Animalia Anthropoda Insecta Diptera Drosophilidae Drosophila melanogaster")
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>>> create_tree("Eukaryota Animalia Chordata Mammalia Primates Hominidae Homo sapiens")
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>>> create_tree("Eukaryota Plantae Magnoliophyta Magnoliopsida Fabales Fabaceae Pisum sativum")
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>>> create_tree("Eukaryota Fungi Basidiomycota Homobasidiomycatae Agaricales Amanitacae Amanita muscaria")
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>>> from django import db
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# Normally, accessing FKs doesn't fill in related objects:
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>>> db.reset_queries()
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>>> fly = Species.objects.get(name="melanogaster")
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>>> fly.genus.family.order.klass.phylum.kingdom.domain
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<Domain: Eukaryota>
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>>> len(db.connection.queries)
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8
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# However, a select_related() call will fill in those related objects without any extra queries:
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>>> db.reset_queries()
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>>> person = Species.objects.select_related(depth=10).get(name="sapiens")
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>>> person.genus.family.order.klass.phylum.kingdom.domain
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<Domain: Eukaryota>
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>>> len(db.connection.queries)
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1
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# select_related() also of course applies to entire lists, not just items.
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# Without select_related()
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>>> db.reset_queries()
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>>> world = Species.objects.all()
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>>> [o.genus.family for o in world]
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[<Family: Drosophilidae>, <Family: Hominidae>, <Family: Fabaceae>, <Family: Amanitacae>]
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>>> len(db.connection.queries)
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9
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# With select_related():
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>>> db.reset_queries()
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>>> world = Species.objects.all().select_related()
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>>> [o.genus.family for o in world]
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[<Family: Drosophilidae>, <Family: Hominidae>, <Family: Fabaceae>, <Family: Amanitacae>]
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>>> len(db.connection.queries)
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1
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# The "depth" argument to select_related() will stop the descent at a particular level:
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>>> db.reset_queries()
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>>> pea = Species.objects.select_related(depth=1).get(name="sativum")
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>>> pea.genus.family.order.klass.phylum.kingdom.domain
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<Domain: Eukaryota>
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# Notice: one fewer queries than above because of depth=1
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>>> len(db.connection.queries)
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7
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>>> db.reset_queries()
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>>> pea = Species.objects.select_related(depth=5).get(name="sativum")
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>>> pea.genus.family.order.klass.phylum.kingdom.domain
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<Domain: Eukaryota>
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>>> len(db.connection.queries)
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3
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>>> db.reset_queries()
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>>> world = Species.objects.all().select_related(depth=2)
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>>> [o.genus.family.order for o in world]
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[<Order: Diptera>, <Order: Primates>, <Order: Fabales>, <Order: Agaricales>]
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>>> len(db.connection.queries)
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5
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>>> s = Species.objects.all().select_related(depth=1).extra(select={'a': 'select_related_species.id + 10'})[0]
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>>> s.id + 10 == s.a
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True
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# The optional fields passed to select_related() control which related models
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# we pull in. This allows for smaller queries and can act as an alternative
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# (or, in addition to) the depth parameter.
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# In the next two cases, we explicitly say to select the 'genus' and
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# 'genus.family' models, leading to the same number of queries as before.
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>>> db.reset_queries()
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>>> world = Species.objects.select_related('genus__family')
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>>> [o.genus.family for o in world]
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[<Family: Drosophilidae>, <Family: Hominidae>, <Family: Fabaceae>, <Family: Amanitacae>]
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>>> len(db.connection.queries)
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1
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>>> db.reset_queries()
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>>> world = Species.objects.filter(genus__name='Amanita').select_related('genus__family')
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>>> [o.genus.family.order for o in world]
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[<Order: Agaricales>]
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>>> len(db.connection.queries)
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2
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>>> db.reset_queries()
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>>> Species.objects.all().select_related('genus__family__order').order_by('id')[0:1].get().genus.family.order.name
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u'Diptera'
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>>> len(db.connection.queries)
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1
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# Specifying both "depth" and fields is an error.
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>>> Species.objects.select_related('genus__family__order', depth=4)
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Traceback (most recent call last):
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...
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TypeError: Cannot pass both "depth" and fields to select_related()
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# Reset DEBUG to where we found it.
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>>> settings.DEBUG = False
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"""}
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return self.name
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