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"""
41. Tests for select_related()
``select_related()`` follows all relationships and pre-caches any foreign key
values so that complex trees can be fetched in a single query. However, this
isn't always a good idea, so the ``depth`` argument control how many "levels"
the select-related behavior will traverse.
"""
from django.db import models
# Who remembers high school biology?
class Domain(models.Model):
name = models.CharField(max_length=50)
def __unicode__(self):
return self.name
class Kingdom(models.Model):
name = models.CharField(max_length=50)
domain = models.ForeignKey(Domain)
def __unicode__(self):
return self.name
class Phylum(models.Model):
name = models.CharField(max_length=50)
kingdom = models.ForeignKey(Kingdom)
def __unicode__(self):
return self.name
class Klass(models.Model):
name = models.CharField(max_length=50)
phylum = models.ForeignKey(Phylum)
def __unicode__(self):
return self.name
class Order(models.Model):
name = models.CharField(max_length=50)
klass = models.ForeignKey(Klass)
def __unicode__(self):
return self.name
class Family(models.Model):
name = models.CharField(max_length=50)
order = models.ForeignKey(Order)
def __unicode__(self):
return self.name
class Genus(models.Model):
name = models.CharField(max_length=50)
family = models.ForeignKey(Family)
def __unicode__(self):
return self.name
class Species(models.Model):
name = models.CharField(max_length=50)
genus = models.ForeignKey(Genus)
def __unicode__(self):
return self.name
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