1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
|
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',)
class Restaurant(Place):
serves_hot_dogs = models.BooleanField(default=False)
serves_pizza = models.BooleanField(default=False)
class ItalianRestaurant(Restaurant):
serves_gnocchi = models.BooleanField(default=False)
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()
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)
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')
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)
class DerivedM(BaseM):
customPK = models.IntegerField(primary_key=True)
derived_name = models.CharField(max_length=100)
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',)
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',)
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
|
