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import datetime
from django.db import models
class Place(models.Model):
name = models.CharField(max_length=50)
address = models.CharField(max_length=80)
class Meta:
ordering = ('name',)
def __str__(self):
return "%s the place" % self.name
class Restaurant(Place):
serves_hot_dogs = models.BooleanField(default=False)
serves_pizza = models.BooleanField(default=False)
def __str__(self):
return "%s the restaurant" % self.name
class ItalianRestaurant(Restaurant):
serves_gnocchi = models.BooleanField(default=False)
def __str__(self):
return "%s the italian restaurant" % self.name
class ParkingLot(Place):
# An explicit link to the parent (we can control the attribute name).
parent = models.OneToOneField(Place, models.CASCADE, primary_key=True, parent_link=True)
capacity = models.IntegerField()
def __str__(self):
return "%s the parking lot" % self.name
class ParkingLot3(Place):
# The parent_link connector need not be the pk on the model.
primary_key = models.AutoField(primary_key=True)
parent = models.OneToOneField(Place, models.CASCADE, parent_link=True)
class ParkingLot4(models.Model):
# Test parent_link connector can be discovered in abstract classes.
parent = models.OneToOneField(Place, models.CASCADE, parent_link=True)
class Meta:
abstract = True
class ParkingLot4A(ParkingLot4, Place):
pass
class ParkingLot4B(Place, ParkingLot4):
pass
class Supplier(models.Model):
name = models.CharField(max_length=50)
restaurant = models.ForeignKey(Restaurant, models.CASCADE)
def __str__(self):
return self.name
class Wholesaler(Supplier):
retailer = models.ForeignKey(Supplier, models.CASCADE, related_name='wholesale_supplier')
class Parent(models.Model):
created = models.DateTimeField(default=datetime.datetime.now)
class Child(Parent):
name = models.CharField(max_length=10)
class SelfRefParent(models.Model):
parent_data = models.IntegerField()
self_data = models.ForeignKey('self', models.SET_NULL, null=True)
class SelfRefChild(SelfRefParent):
child_data = models.IntegerField()
class Article(models.Model):
headline = models.CharField(max_length=100)
pub_date = models.DateTimeField()
class Meta:
ordering = ('-pub_date', 'headline')
def __str__(self):
return self.headline
class ArticleWithAuthor(Article):
author = models.CharField(max_length=100)
class M2MBase(models.Model):
articles = models.ManyToManyField(Article)
class M2MChild(M2MBase):
name = models.CharField(max_length=50)
class Evaluation(Article):
quality = models.IntegerField()
class Meta:
abstract = True
class QualityControl(Evaluation):
assignee = models.CharField(max_length=50)
class BaseM(models.Model):
base_name = models.CharField(max_length=100)
def __str__(self):
return self.base_name
class DerivedM(BaseM):
customPK = models.IntegerField(primary_key=True)
derived_name = models.CharField(max_length=100)
def __str__(self):
return "PK = %d, base_name = %s, derived_name = %s" % (
self.customPK, self.base_name, self.derived_name)
class AuditBase(models.Model):
planned_date = models.DateField()
class Meta:
abstract = True
verbose_name_plural = 'Audits'
class CertificationAudit(AuditBase):
class Meta(AuditBase.Meta):
abstract = True
class InternalCertificationAudit(CertificationAudit):
auditing_dept = models.CharField(max_length=20)
# Abstract classes don't get m2m tables autocreated.
class Person(models.Model):
name = models.CharField(max_length=100)
class Meta:
ordering = ('name',)
def __str__(self):
return self.name
class AbstractEvent(models.Model):
name = models.CharField(max_length=100)
attendees = models.ManyToManyField(Person, related_name="%(class)s_set")
class Meta:
abstract = True
ordering = ('name',)
def __str__(self):
return self.name
class BirthdayParty(AbstractEvent):
pass
class BachelorParty(AbstractEvent):
pass
class MessyBachelorParty(BachelorParty):
pass
# Check concrete -> abstract -> concrete inheritance
class SearchableLocation(models.Model):
keywords = models.CharField(max_length=255)
class Station(SearchableLocation):
name = models.CharField(max_length=128)
class Meta:
abstract = True
class BusStation(Station):
inbound = models.BooleanField(default=False)
class TrainStation(Station):
zone = models.IntegerField()
class User(models.Model):
username = models.CharField(max_length=30, unique=True)
class Profile(User):
profile_id = models.AutoField(primary_key=True)
extra = models.CharField(max_length=30, blank=True)
# Check concrete + concrete -> concrete -> concrete
class Politician(models.Model):
politician_id = models.AutoField(primary_key=True)
title = models.CharField(max_length=50)
class Congressman(Person, Politician):
state = models.CharField(max_length=2)
class Senator(Congressman):
pass
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