below is ext.declarative.py's doc: class Person(Base): __tablename__ = 'people' id = Column(Integer, primary_key=True) discriminator = Column(String(50)) __mapper_args__ = {'polymorphic_on': discriminator}
class Engineer(Person): __tablename__ = 'engineers' __mapper_args__ = {'polymorphic_identity': 'engineer'} id = Column(Integer, ForeignKey('people.id'), primary_key=True) primary_language = Column(String(50)) For single-table inheritance, the ``__tablename__`` and ``__table__`` class variables are optional on a class when the class inherits from another mapped class. according it i think it should be like this: class Engineer(Person): __mapper_args__ = {'polymorphic_identity': 'engineer'} primary_language = Column(String(50)) but : File "c:\python25\lib\site-packages\sqlalchemy-0.5.0rc1-py2.5.egg \sqlalchemy\s ql\expression.py", line 2636, in description return self.name.encode('ascii', 'backslashreplace') AttributeError: 'NoneType' object has no attribute 'encode' what should i do? thanks --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "sqlalchemy" group. To post to this group, send email to sqlalchemy@googlegroups.com To unsubscribe from this group, send email to sqlalchemy+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~----------~----~----~----~------~----~------~--~---