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
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
|
from sqlalchemy import ForeignKey
from sqlalchemy import Integer
from sqlalchemy import String
from sqlalchemy.orm import class_mapper
from sqlalchemy.orm import create_session
from sqlalchemy.orm import mapper
from sqlalchemy.orm import polymorphic_union
from sqlalchemy.orm import relationship
from sqlalchemy.orm.interfaces import MANYTOONE
from sqlalchemy.orm.interfaces import ONETOMANY
from sqlalchemy.testing import fixtures
from sqlalchemy.testing.schema import Column
from sqlalchemy.testing.schema import Table
def produce_test(parent, child, direction):
"""produce a testcase for A->B->C inheritance with a self-referential
relationship between two of the classes, using either one-to-many or
many-to-one.
the old "no discriminator column" pattern is used.
"""
class ABCTest(fixtures.MappedTest):
@classmethod
def define_tables(cls, metadata):
global ta, tb, tc
ta = ["a", metadata]
ta.append(
Column(
"id",
Integer,
primary_key=True,
test_needs_autoincrement=True,
)
),
ta.append(Column("a_data", String(30)))
if "a" == parent and direction == MANYTOONE:
ta.append(
Column(
"child_id",
Integer,
ForeignKey(
"%s.id" % child, use_alter=True, name="foo"
),
)
)
elif "a" == child and direction == ONETOMANY:
ta.append(
Column(
"parent_id",
Integer,
ForeignKey(
"%s.id" % parent, use_alter=True, name="foo"
),
)
)
ta = Table(*ta)
tb = ["b", metadata]
tb.append(
Column("id", Integer, ForeignKey("a.id"), primary_key=True)
)
tb.append(Column("b_data", String(30)))
if "b" == parent and direction == MANYTOONE:
tb.append(
Column(
"child_id",
Integer,
ForeignKey(
"%s.id" % child, use_alter=True, name="foo"
),
)
)
elif "b" == child and direction == ONETOMANY:
tb.append(
Column(
"parent_id",
Integer,
ForeignKey(
"%s.id" % parent, use_alter=True, name="foo"
),
)
)
tb = Table(*tb)
tc = ["c", metadata]
tc.append(
Column("id", Integer, ForeignKey("b.id"), primary_key=True)
)
tc.append(Column("c_data", String(30)))
if "c" == parent and direction == MANYTOONE:
tc.append(
Column(
"child_id",
Integer,
ForeignKey(
"%s.id" % child, use_alter=True, name="foo"
),
)
)
elif "c" == child and direction == ONETOMANY:
tc.append(
Column(
"parent_id",
Integer,
ForeignKey(
"%s.id" % parent, use_alter=True, name="foo"
),
)
)
tc = Table(*tc)
def teardown(self):
if direction == MANYTOONE:
parent_table = {"a": ta, "b": tb, "c": tc}[parent]
parent_table.update(
values={parent_table.c.child_id: None}
).execute()
elif direction == ONETOMANY:
child_table = {"a": ta, "b": tb, "c": tc}[child]
child_table.update(
values={child_table.c.parent_id: None}
).execute()
super(ABCTest, self).teardown()
def test_roundtrip(self):
parent_table = {"a": ta, "b": tb, "c": tc}[parent]
child_table = {"a": ta, "b": tb, "c": tc}[child]
remote_side = None
if direction == MANYTOONE:
foreign_keys = [parent_table.c.child_id]
elif direction == ONETOMANY:
foreign_keys = [child_table.c.parent_id]
atob = ta.c.id == tb.c.id
btoc = tc.c.id == tb.c.id
if direction == ONETOMANY:
relationshipjoin = parent_table.c.id == child_table.c.parent_id
elif direction == MANYTOONE:
relationshipjoin = parent_table.c.child_id == child_table.c.id
if parent is child:
remote_side = [child_table.c.id]
abcjoin = polymorphic_union(
{
"a": ta.select(
tb.c.id == None, # noqa
from_obj=[ta.outerjoin(tb, onclause=atob)],
),
"b": ta.join(tb, onclause=atob)
.outerjoin(tc, onclause=btoc)
.select(tc.c.id == None)
.reduce_columns(), # noqa
"c": tc.join(tb, onclause=btoc).join(ta, onclause=atob),
},
"type",
"abcjoin",
)
bcjoin = polymorphic_union(
{
"b": ta.join(tb, onclause=atob)
.outerjoin(tc, onclause=btoc)
.select(tc.c.id == None)
.reduce_columns(), # noqa
"c": tc.join(tb, onclause=btoc).join(ta, onclause=atob),
},
"type",
"bcjoin",
)
class A(object):
def __init__(self, name):
self.a_data = name
class B(A):
pass
class C(B):
pass
mapper(
A,
ta,
polymorphic_on=abcjoin.c.type,
with_polymorphic=("*", abcjoin),
polymorphic_identity="a",
)
mapper(
B,
tb,
polymorphic_on=bcjoin.c.type,
with_polymorphic=("*", bcjoin),
polymorphic_identity="b",
inherits=A,
inherit_condition=atob,
)
mapper(
C,
tc,
polymorphic_identity="c",
inherits=B,
inherit_condition=btoc,
)
parent_mapper = class_mapper({ta: A, tb: B, tc: C}[parent_table])
child_mapper = class_mapper({ta: A, tb: B, tc: C}[child_table])
parent_class = parent_mapper.class_
child_class = child_mapper.class_
parent_mapper.add_property(
"collection",
relationship(
child_mapper,
primaryjoin=relationshipjoin,
foreign_keys=foreign_keys,
order_by=child_mapper.c.id,
remote_side=remote_side,
uselist=True,
),
)
sess = create_session()
parent_obj = parent_class("parent1")
child_obj = child_class("child1")
somea = A("somea")
someb = B("someb")
somec = C("somec")
# print "APPENDING", parent.__class__.__name__ , "TO",
# child.__class__.__name__
sess.add(parent_obj)
parent_obj.collection.append(child_obj)
if direction == ONETOMANY:
child2 = child_class("child2")
parent_obj.collection.append(child2)
sess.add(child2)
elif direction == MANYTOONE:
parent2 = parent_class("parent2")
parent2.collection.append(child_obj)
sess.add(parent2)
sess.add(somea)
sess.add(someb)
sess.add(somec)
sess.flush()
sess.expunge_all()
# assert result via direct get() of parent object
result = sess.query(parent_class).get(parent_obj.id)
assert result.id == parent_obj.id
assert result.collection[0].id == child_obj.id
if direction == ONETOMANY:
assert result.collection[1].id == child2.id
elif direction == MANYTOONE:
result2 = sess.query(parent_class).get(parent2.id)
assert result2.id == parent2.id
assert result2.collection[0].id == child_obj.id
sess.expunge_all()
# assert result via polymorphic load of parent object
result = sess.query(A).filter_by(id=parent_obj.id).one()
assert result.id == parent_obj.id
assert result.collection[0].id == child_obj.id
if direction == ONETOMANY:
assert result.collection[1].id == child2.id
elif direction == MANYTOONE:
result2 = sess.query(A).filter_by(id=parent2.id).one()
assert result2.id == parent2.id
assert result2.collection[0].id == child_obj.id
ABCTest.__name__ = "Test%sTo%s%s" % (
parent,
child,
(direction is ONETOMANY and "O2M" or "M2O"),
)
return ABCTest
# test all combinations of polymorphic a/b/c related to another of a/b/c
for parent in ["a", "b", "c"]:
for child in ["a", "b", "c"]:
for direction in [ONETOMANY, MANYTOONE]:
testclass = produce_test(parent, child, direction)
exec("%s = testclass" % testclass.__name__)
del testclass
del produce_test
|
