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
204
|
from django.db import models
from datetime import datetime
from django.contrib.auth.models import User
# Forward declared intermediate model
class Membership(models.Model):
person = models.ForeignKey('Person')
group = models.ForeignKey('Group')
date_joined = models.DateTimeField(default=datetime.now)
def __unicode__(self):
return "%s is a member of %s" % (self.person.name, self.group.name)
class UserMembership(models.Model):
user = models.ForeignKey(User)
group = models.ForeignKey('Group')
date_joined = models.DateTimeField(default=datetime.now)
def __unicode__(self):
return "%s is a user and member of %s" % (self.user.username, self.group.name)
class Person(models.Model):
name = models.CharField(max_length=128)
def __unicode__(self):
return self.name
class Group(models.Model):
name = models.CharField(max_length=128)
# Membership object defined as a class
members = models.ManyToManyField(Person, through=Membership)
user_members = models.ManyToManyField(User, through='UserMembership')
def __unicode__(self):
return self.name
__test__ = {'API_TESTS':"""
# Create some dummy data
>>> bob = Person.objects.create(name='Bob')
>>> jim = Person.objects.create(name='Jim')
>>> rock = Group.objects.create(name='Rock')
>>> roll = Group.objects.create(name='Roll')
>>> frank = User.objects.create_user('frank','frank@example.com','password')
>>> jane = User.objects.create_user('jane','jane@example.com','password')
# Now test that the forward declared Membership works
>>> Membership.objects.create(person=bob, group=rock)
<Membership: Bob is a member of Rock>
>>> Membership.objects.create(person=bob, group=roll)
<Membership: Bob is a member of Roll>
>>> Membership.objects.create(person=jim, group=rock)
<Membership: Jim is a member of Rock>
>>> bob.group_set.all()
[<Group: Rock>, <Group: Roll>]
>>> roll.members.all()
[<Person: Bob>]
# Error messages use the model name, not repr of the class name
>>> bob.group_set = []
Traceback (most recent call last):
...
AttributeError: Cannot set values on a ManyToManyField which specifies an intermediary model. Use Membership's Manager instead.
>>> roll.members = []
Traceback (most recent call last):
...
AttributeError: Cannot set values on a ManyToManyField which specifies an intermediary model. Use Membership's Manager instead.
>>> rock.members.create(name='Anne')
Traceback (most recent call last):
...
AttributeError: Cannot use create() on a ManyToManyField which specifies an intermediary model. Use Membership's Manager instead.
>>> bob.group_set.create(name='Funk')
Traceback (most recent call last):
...
AttributeError: Cannot use create() on a ManyToManyField which specifies an intermediary model. Use Membership's Manager instead.
# Now test that the intermediate with a relationship outside
# the current app (i.e., UserMembership) workds
>>> UserMembership.objects.create(user=frank, group=rock)
<UserMembership: frank is a user and member of Rock>
>>> UserMembership.objects.create(user=frank, group=roll)
<UserMembership: frank is a user and member of Roll>
>>> UserMembership.objects.create(user=jane, group=rock)
<UserMembership: jane is a user and member of Rock>
>>> frank.group_set.all()
[<Group: Rock>, <Group: Roll>]
>>> roll.user_members.all()
[<User: frank>]
"""}
from django.db import models
from datetime import datetime
from django.contrib.auth.models import User
# Forward declared intermediate model
class Membership(models.Model):
person = models.ForeignKey('Person')
group = models.ForeignKey('Group')
date_joined = models.DateTimeField(default=datetime.now)
def __unicode__(self):
return "%s is a member of %s" % (self.person.name, self.group.name)
class UserMembership(models.Model):
user = models.ForeignKey(User)
group = models.ForeignKey('Group')
date_joined = models.DateTimeField(default=datetime.now)
def __unicode__(self):
return "%s is a user and member of %s" % (self.user.username, self.group.name)
class Person(models.Model):
name = models.CharField(max_length=128)
def __unicode__(self):
return self.name
class Group(models.Model):
name = models.CharField(max_length=128)
# Membership object defined as a class
members = models.ManyToManyField(Person, through=Membership)
user_members = models.ManyToManyField(User, through='UserMembership')
def __unicode__(self):
return self.name
__test__ = {'API_TESTS':"""
# Create some dummy data
>>> bob = Person.objects.create(name='Bob')
>>> jim = Person.objects.create(name='Jim')
>>> rock = Group.objects.create(name='Rock')
>>> roll = Group.objects.create(name='Roll')
>>> frank = User.objects.create_user('frank','frank@example.com','password')
>>> jane = User.objects.create_user('jane','jane@example.com','password')
# Now test that the forward declared Membership works
>>> Membership.objects.create(person=bob, group=rock)
<Membership: Bob is a member of Rock>
>>> Membership.objects.create(person=bob, group=roll)
<Membership: Bob is a member of Roll>
>>> Membership.objects.create(person=jim, group=rock)
<Membership: Jim is a member of Rock>
>>> bob.group_set.all()
[<Group: Rock>, <Group: Roll>]
>>> roll.members.all()
[<Person: Bob>]
# Error messages use the model name, not repr of the class name
>>> bob.group_set = []
Traceback (most recent call last):
...
AttributeError: Cannot set values on a ManyToManyField which specifies an intermediary model. Use Membership's Manager instead.
>>> roll.members = []
Traceback (most recent call last):
...
AttributeError: Cannot set values on a ManyToManyField which specifies an intermediary model. Use Membership's Manager instead.
>>> rock.members.create(name='Anne')
Traceback (most recent call last):
...
AttributeError: Cannot use create() on a ManyToManyField which specifies an intermediary model. Use Membership's Manager instead.
>>> bob.group_set.create(name='Funk')
Traceback (most recent call last):
...
AttributeError: Cannot use create() on a ManyToManyField which specifies an intermediary model. Use Membership's Manager instead.
# Now test that the intermediate with a relationship outside
# the current app (i.e., UserMembership) workds
>>> UserMembership.objects.create(user=frank, group=rock)
<UserMembership: frank is a user and member of Rock>
>>> UserMembership.objects.create(user=frank, group=roll)
<UserMembership: frank is a user and member of Roll>
>>> UserMembership.objects.create(user=jane, group=rock)
<UserMembership: jane is a user and member of Rock>
>>> frank.group_set.all()
[<Group: Rock>, <Group: Roll>]
>>> roll.user_members.all()
[<User: frank>]
"""}
|
