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from sqlalchemy import ForeignKey
from sqlalchemy import Integer
from sqlalchemy import String
from sqlalchemy import testing
from sqlalchemy.orm import class_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.fixtures import fixture_session
from sqlalchemy.testing.schema import Column
from sqlalchemy.testing.schema import Table
def _combinations():
for parent in ["a", "b", "c"]:
for child in ["a", "b", "c"]:
for direction in [ONETOMANY, MANYTOONE]:
name = "Test%sTo%s%s" % (
parent,
child,
(direction is ONETOMANY and "O2M" or "M2O"),
)
yield (name, parent, child, direction)
@testing.combinations(
*list(_combinations()), argnames="name,parent,child,direction", id_="saaa"
)
class ABCTest(fixtures.MappedTest):
@classmethod
def define_tables(cls, metadata):
parent, child, direction = cls.parent, cls.child, cls.direction
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)
@classmethod
def setup_mappers(cls):
parent, child, direction = cls.parent, cls.child, cls.direction
ta, tb, tc = cls.tables("a", "b", "c")
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()
.where(tb.c.id == None) # noqa
.select_from(ta.outerjoin(tb, onclause=atob))
.subquery(),
"b": ta.join(tb, onclause=atob)
.outerjoin(tc, onclause=btoc)
.select()
.where(tc.c.id == None)
.reduce_columns()
.subquery(), # 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()
.where(tc.c.id == None)
.reduce_columns()
.subquery(), # noqa
"c": tc.join(tb, onclause=btoc).join(ta, onclause=atob),
},
"type",
"bcjoin",
)
class A(cls.Comparable):
def __init__(self, name):
self.a_data = name
class B(A):
pass
class C(B):
pass
cls.mapper_registry.map_imperatively(
A,
ta,
polymorphic_on=abcjoin.c.type,
with_polymorphic=("*", abcjoin),
polymorphic_identity="a",
)
cls.mapper_registry.map_imperatively(
B,
tb,
polymorphic_on=bcjoin.c.type,
with_polymorphic=("*", bcjoin),
polymorphic_identity="b",
inherits=A,
inherit_condition=atob,
)
cls.mapper_registry.map_imperatively(
C,
tc,
polymorphic_identity="c",
with_polymorphic=("*", tc.join(tb, btoc).join(ta, atob)),
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_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,
),
)
def test_roundtrip(self):
parent, child, direction = self.parent, self.child, self.direction
A, B, C = self.classes("A", "B", "C")
parent_class = {"a": A, "b": B, "c": C}[parent]
child_class = {"a": A, "b": B, "c": C}[child]
sess = fixture_session(autoflush=False, expire_on_commit=False)
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.commit()
sess.close()
# assert result via direct get() of parent object
result = sess.get(parent_class, 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.get(parent_class, 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
|
