Hi,
I have a class which represents a table with polymorphic enabled. When I
directly access to this table the polymorphic mechanism adds the needed
condition and everything works perfectly. However when this table is joined to
a request the condition is missing…
I attached a quick sample to this email.
My output:
2014-10-10 00:18:44,582 INFO sqlalchemy.engine.base.Engine SELECT
"myTable"."otherId" AS "myTable_otherId"
FROM "myTable"
WHERE "myTable".id = ? AND "myTable".flag IN (?)
2014-10-10 00:18:44,582 INFO sqlalchemy.engine.base.Engine (1, 1)
A contains 2
A contains 3
2014-10-10 00:18:44,583 INFO sqlalchemy.engine.base.Engine SELECT
"otherTable".id AS "otherTable_id", "myTable"."otherId" AS "myTable_otherId"
FROM "otherTable" JOIN "myTable" ON "myTable".id = "otherTable".id
2014-10-10 00:18:44,583 INFO sqlalchemy.engine.base.Engine ()
Now A contains 2
Now A contains 3
Now A contains 4
Now A contains 5
The last lines are not part of the A class due to the polymorphic constraint…
However they are present since the polymorphic condition is missing.
Maybe I missed something?
Thank you for your help.
Sincerely
Aurélien
#!/usr/bin/python2.7
from sqlalchemy import Column, Integer, Boolean, create_engine
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy.orm import sessionmaker
Base = declarative_base()
class _motherClass(Base):
__tablename__ = 'myTable'
id = Column(Integer(unsigned=True), primary_key=True)
otherId = Column(Integer(unsigned=True), primary_key=True)
flag = Column(Boolean, primary_key=True)
__mapper_args__ = {
'polymorphic_on' : flag,
}
def __init__(self, id, otherId) :
self.id = id
self.otherId = otherId
class A(_motherClass) :
__mapper_args__ = {
'polymorphic_identity' : True,
}
class B(_motherClass) :
__mapper_args__ = {
'polymorphic_identity' : False,
}
class OtherTable(Base) :
__tablename__ = 'otherTable'
id = Column(Integer(unsigned=True), primary_key=True)
engine = create_engine('sqlite:///test.sqlite3', echo=True)
session = sessionmaker(bind=engine)()
Base.metadata.create_all(engine)
session.add(A(1, 2))
session.add(A(1, 3))
session.add(B(1, 4))
session.add(B(1, 5))
session.add(OtherTable(id=1))
session.commit()
for (otherId,) in session.query(A.otherId).filter(A.id == 1) :
print('A contains %s' % otherId)
for (id, otherId,) in session.query(OtherTable.id, A.otherId).join(A, A.id == OtherTable.id) :
print('Now A contains %s' % otherId)
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