'RelationshipProperty' object has no attribute 'c' error in sqlalchemy

I'm having a lot of trouble implementing SQLalchemy for a legacy MSSQL database. It is a big existing database, so I wanted to use sqlautocode to generate the files for me, because using autoload to reflect the database takes too long.

The first problem was that sqlautocode no longer seems to work on SQLalchemy 0.8. I did still have existing output from an earlier version, so I thought I'd use that, just to test with.

Now sqlautocode outputs the 'classical mapping', which is not really a problem, but whenever I tried to use a foreign key, 'RelationshipProperty' object has no attribute 'c' would show up. An error somewhere deep inside the SQLalchemy library.

So next, I tried just skipping sqlautocode and writing the classes and relations myself, going by this code for SQLalchemy 0.8. I used two example tables and I got the exact same error. Then I commented out most of the columns, all of the relations and I -STILL- get the error.

Below is my code:

from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy import Column, ForeignKey
from sqlalchemy.orm import relationship, backref
from sqlalchemy.dialects.mssql import *

Base = declarative_base()


class PeopleMemberhip(Base):
    __tablename__ = 'people_memberships'

    ppl_mshp_id = Column(VARCHAR(length=36), primary_key=True, nullable=False)
    ppl_mshp_startdate = Column(DATETIME())
    ppl_mshp_enddate = Column(DATETIME())
    # ppl_mshp_pmsd_id = Column(VARCHAR(length=36), ForeignKey('paymentschedules.pmsd_id'))

    # paymentschedule = relationship("PaymentSchedule", backref=backref('people_memberships'))

    def __repr__(self):
        return "<people_membership('%s','%s')>" % (self.ppl_mshp_id, self.ppl_mshp_startdate)


class PaymentSchedule(Base):
    __tablename__ = 'paymentschedules'

    pmsd_id = Column(VARCHAR(length=36), primary_key=True, nullable=False)
    pmsd_name = Column(NVARCHAR(length=60))
    pmsd_startdate = Column(DATETIME())
    pmsd_enddate = Column(DATETIME())

    # paymentschedule = relationship("PaymentSchedule", backref=backref('people_memberships'))

    def __repr__(self):
        return "<paymentschedule('%s','%s')>" % (self.pmsd_id, self.pmsd_name)

And the resulting Error:

Traceback (most recent call last):
  File "C:\Program Files (x86)\JetBrains\PyCharm 2.7\helpers\pydev\pydevd.py", line 1472, in <module>
    debugger.run(setup['file'], None, None)
  File "C:\Program Files (x86)\JetBrains\PyCharm 2.7\helpers\pydev\pydevd.py", line 1116, in run
    pydev_imports.execfile(file, globals, locals) #execute the script
  File "C:/Users/erik/workspace/flasktest/test.py", line 16, in <module>
    contract = db.session.query(PeopleMemberhip).filter_by(ppl_mshp_id='98ABD7E9-4CFF-4F7B-8537-8E46FD5C79D5').one()
  File "C:\Users\erik\workspace\flasktest\lib\site-packages\sqlalchemy\orm\scoping.py", line 149, in do
    return getattr(self.registry(), name)(*args, **kwargs)
  File "C:\Users\erik\workspace\flasktest\lib\site-packages\sqlalchemy\orm\session.py", line 1105, in query
    return self._query_cls(entities, self, **kwargs)
  File "C:\Users\erik\workspace\flasktest\lib\site-packages\sqlalchemy\orm\query.py", line 115, in __init__
    self._set_entities(entities)
  File "C:\Users\erik\workspace\flasktest\lib\site-packages\sqlalchemy\orm\query.py", line 124, in _set_entities
    self._set_entity_selectables(self._entities)
  File "C:\Users\erik\workspace\flasktest\lib\site-packages\sqlalchemy\orm\query.py", line 157, in _set_entity_selectables
    ent.setup_entity(*d[entity])
  File "C:\Users\erik\workspace\flasktest\lib\site-packages\sqlalchemy\orm\query.py", line 2744, in setup_entity
    self._with_polymorphic = ext_info.with_polymorphic_mappers
  File "C:\Users\erik\workspace\flasktest\lib\site-packages\sqlalchemy\util\langhelpers.py", line 582, in __get__
    obj.__dict__[self.__name__] = result = self.fget(obj)
  File "C:\Users\erik\workspace\flasktest\lib\site-packages\sqlalchemy\orm\mapper.py", line 1425, in _with_polymorphic_mappers
    configure_mappers()
  File "C:\Users\erik\workspace\flasktest\lib\site-packages\sqlalchemy\orm\mapper.py", line 2106, in configure_mappers
    mapper._post_configure_properties()
  File "C:\Users\erik\workspace\flasktest\lib\site-packages\sqlalchemy\orm\mapper.py", line 1242, in _post_configure_properties
    prop.init()
  File "C:\Users\erik\workspace\flasktest\lib\site-packages\sqlalchemy\orm\interfaces.py", line 231, in init
    self.do_init()
  File "C:\Users\erik\workspace\flasktest\lib\site-packages\sqlalchemy\orm\properties.py", line 1028, in do_init
    self._setup_join_conditions()
  File "C:\Users\erik\workspace\flasktest\lib\site-packages\sqlalchemy\orm\properties.py", line 1102, in _setup_join_conditions
    can_be_synced_fn=self._columns_are_mapped
  File "C:\Users\erik\workspace\flasktest\lib\site-packages\sqlalchemy\orm\relationships.py", line 115, in __init__
    self._annotate_fks()
  File "C:\Users\erik\workspace\flasktest\lib\site-packages\sqlalchemy\orm\relationships.py", line 311, in _annotate_fks
    self._annotate_present_fks()
  File "C:\Users\erik\workspace\flasktest\lib\site-packages\sqlalchemy\orm\relationships.py", line 331, in _annotate_present_fks
    secondarycols = util.column_set(self.secondary.c)
AttributeError: 'RelationshipProperty' object has no attribute 'c'

I'm really at a loss, any help with this error is appreciated, but also if someone can suggest a different approach that can make SQLalchemy work with our legacy MSSQL database it is also a solution.

As I said, sqlautocode doesn't seem to work any more, but maybe I'm using it the wrong way, or maybe there is an alternative tool I don't know about.

Erik