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from sqlalchemy import *
from sqlalchemy.orm import *
from sqlalchemy.orm.interfaces import ONETOMANY, MANYTOONE
from sqlalchemy import testing
from sqlalchemy.testing.schema import Table, Column
from sqlalchemy.testing import fixtures
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, from_obj=[ta.outerjoin(tb, onclause=atob)]),
"b":ta.join(tb, onclause=atob).outerjoin(tc, onclause=btoc).select(tc.c.id==None).reduce_columns(),
"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(),
"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
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