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"""
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.contrib.contenttypes.fields import (
GenericForeignKey, GenericRelation,
)
from django.contrib.contenttypes.models import ContentType
from django.db import models
from django.utils.encoding import python_2_unicode_compatible
# Who remembers high school biology?
@python_2_unicode_compatible
class Domain(models.Model):
name = models.CharField(max_length=50)
def __str__(self):
return self.name
@python_2_unicode_compatible
class Kingdom(models.Model):
name = models.CharField(max_length=50)
domain = models.ForeignKey(Domain)
def __str__(self):
return self.name
@python_2_unicode_compatible
class Phylum(models.Model):
name = models.CharField(max_length=50)
kingdom = models.ForeignKey(Kingdom)
def __str__(self):
return self.name
@python_2_unicode_compatible
class Klass(models.Model):
name = models.CharField(max_length=50)
phylum = models.ForeignKey(Phylum)
def __str__(self):
return self.name
@python_2_unicode_compatible
class Order(models.Model):
name = models.CharField(max_length=50)
klass = models.ForeignKey(Klass)
def __str__(self):
return self.name
@python_2_unicode_compatible
class Family(models.Model):
name = models.CharField(max_length=50)
order = models.ForeignKey(Order)
def __str__(self):
return self.name
@python_2_unicode_compatible
class Genus(models.Model):
name = models.CharField(max_length=50)
family = models.ForeignKey(Family)
def __str__(self):
return self.name
@python_2_unicode_compatible
class Species(models.Model):
name = models.CharField(max_length=50)
genus = models.ForeignKey(Genus)
def __str__(self):
return self.name
# and we'll invent a new thing so we have a model with two foreign keys
@python_2_unicode_compatible
class HybridSpecies(models.Model):
name = models.CharField(max_length=50)
parent_1 = models.ForeignKey(Species, related_name='child_1')
parent_2 = models.ForeignKey(Species, related_name='child_2')
def __str__(self):
return self.name
@python_2_unicode_compatible
class Topping(models.Model):
name = models.CharField(max_length=30)
def __str__(self):
return self.name
@python_2_unicode_compatible
class Pizza(models.Model):
name = models.CharField(max_length=100)
toppings = models.ManyToManyField(Topping)
def __str__(self):
return self.name
@python_2_unicode_compatible
class TaggedItem(models.Model):
tag = models.CharField(max_length=30)
content_type = models.ForeignKey(ContentType, related_name='select_related_tagged_items')
object_id = models.PositiveIntegerField()
content_object = GenericForeignKey('content_type', 'object_id')
def __str__(self):
return self.tag
@python_2_unicode_compatible
class Bookmark(models.Model):
url = models.URLField()
tags = GenericRelation(TaggedItem)
def __str__(self):
return self.url
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