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from django.db import models
from polymodels.fields import PolymorphicTypeField
from polymodels.models import PolymorphicModel
class Zoo(models.Model):
animals = models.ManyToManyField("Animal", related_name="zoos")
class Animal(PolymorphicModel):
name = models.CharField(max_length=50)
class Meta:
ordering = ["id"]
def __str__(self):
return self.name
class NotInstalledAnimal(Animal):
class Meta:
app_label = "not_installed"
class Mammal(Animal):
pass
class Monkey(Mammal):
friends = models.ManyToManyField("self")
class Trait(PolymorphicModel):
trait_type = PolymorphicTypeField(
"self", on_delete=models.CASCADE, blank=True, null=True
)
mammal_type = PolymorphicTypeField(
Mammal, on_delete=models.CASCADE, blank=True, null=True
)
snake_type = PolymorphicTypeField("Snake", on_delete=models.CASCADE)
class AcknowledgedTrait(Trait):
class Meta:
proxy = True
class Reptile(Animal):
length = models.SmallIntegerField()
class Meta:
abstract = True
ordering = ["id"]
class Snake(Reptile):
color = models.CharField(max_length=100, blank=True)
class Meta:
ordering = ["id"]
class BigSnake(Snake):
class Meta:
proxy = True
class HugeSnake(BigSnake):
class Meta:
proxy = True
|
