Hello sqlalchemy-users,
I have some problems when I try to use polymorphic objects with
relation one to many (attached file will show problem).
In short words problem is following:
I create a mapper that is inherited from another mapper and I create a
table with "one to many" relation with "base" mapper.
And when I select related objects using relation property I get all
objects from "related" table, not just those with matching foreign
key. (In case if I expalined poorly, I attached example script to show
this problem).
Am I doing something wrong? Or is that a problem with sqlaclhemy?
--
Best regards,
Vasily mailto:[EMAIL PROTECTED]
from sqlalchemy import *
import sys
class SqlStrMixing( object ):
def __str__( self ):
s = [ self.__class__.__name__ + ': ' ]
for c in self.c:
s.append( u'%s=%s ' % ( c.key, getattr(self, c.key) ) )
result = u''.join(s).encode('ascii')
return result
db = create_engine('sqlite://', echo=True, echo_uow=False)
people = Table('people', db,
Column('person_id', Integer, primary_key=True),
Column('name', String(50)))
engineers = Table('engineers', db,
Column('person_id', Integer, ForeignKey('people.person_id'),
primary_key=True),
Column('status', String(30)),
Column('engineer_name', String(50)),
Column('primary_language', String(50)),
)
managers = Table('managers', db,
Column('person_id', Integer, ForeignKey('people.person_id'),
primary_key=True),
Column('status', String(30)),
Column('manager_name', String(50))
)
accounts = Table('accounts', db,
Column('account_id', Integer, primary_key=True),
Column('xxperson_id', Integer, ForeignKey('people.person_id')),
Column('name', String(50)))
people.create()
engineers.create()
managers.create()
accounts.create()
class Person(SqlStrMixing):
pass
class Engineer(SqlStrMixing):
pass
class Manager(SqlStrMixing):
pass
class Account(SqlStrMixing):
pass
assign_mapper(Account, accounts)
assign_mapper(Person, people,
properties={
'accounts' : relation(Account.mapper, private=True) }
)
assign_mapper(Engineer, engineers, inherits=Person.mapper)
assign_mapper(Manager, managers, inherits=Person.mapper)
john = Engineer(status='Status', engineer_name='John',
primary_language='Python')
john.accounts.append(Account(name="John's account"))
jack = Engineer(status='Status', engineer_name='Jack', primary_language='Java')
jack.accounts.append(Account(name="Jack's account"))
objectstore.commit()
objectstore.clear()
[john, jack] = Engineer.select()
# Gives incorect results: prints two(!!!) accounts
print john
print 'accounts:'
for acc in john.accounts:
print acc
# Gives incorrect results: prints two(!!!) accounts
print
print jack
print 'accounts:'
for acc in jack.accounts:
print acc
# Gives correct results: prints one account
print
for acc in Account.select_by(person_id=john.person_id):
print acc
