very simple and was fixed in r4720.
On May 10, 2008, at 12:48 PM, Michael Bayer wrote:
>
> seems like a bug whereby when it sees the "Manager" single table
> inheritor, it somehow doesn't get the message to synchronize the
> "Employee" primary key column with the Person primary key column.
> I'll have a look at it later today.
>
>
> On May 9, 2008, at 7:49 PM, Fernando Zunino wrote:
>
>>
>> Hi,
>> is it possible to combine joined and single table inheritance in the
>> same inheritance hierarchy?
>>
>> In the code at the bottom I want to use the persons table as a base
>> for the Person, Employee and Manager classes and the employees table
>> to store the particular fields of Employee and Manager.
>>
>> I've run this code using PostgreSql and it correctly flushes the
>> Person and Employee instances but when it wants to flush the Manager
>> instance gives the following error:
>>
>> /home/fernando/.pythonrepo/SQLAlchemy-0.4.5-py2.5.egg/sqlalchemy/
>> engine/base.py in _handle_dbapi_exception(self, e, statement,
>> parameters, cursor)
>> 940 if self.__close_with_result:
>> 941 self.close()
>> --> 942 raise exceptions.DBAPIError.instance(statement,
>> parameters, e, connection_invalidated=is_disconnect)
>> 943 finally:
>> 944 del self._reentrant_error
>>
>> <class 'sqlalchemy.exceptions.ProgrammingError'>: (ProgrammingError)
>> relation "employees_person_id_seq" does not exist
>> 'select nextval(\'"employees_person_id_seq"\')' None
>>
>> Anyone have any suggestions?
>>
>> thanks,
>> Fernando
>>
>>
>> class Person(object):
>> def __init__(self, name):
>> self.name = name
>> def __repr__(self):
>> return self.__class__.__name__ + " " + self.name
>>
>> class Employee(Person):
>> def __init__(self, name, employee_data):
>> self.name = name
>> self.employee_data = employee_data
>>
>> def __repr__(self):
>> return self.__class__.__name__ + " " + self.name + " " +
>> self.employee_data
>>
>> class Manager(Employee):
>> def __init__(self, name, employee_data, manager_data):
>> self.name = name
>> self.employee_data = employee_data
>> self.manager_data = manager_data
>>
>> def __repr__(self):
>> return self.__class__.__name__ + " " + self.name + " " +
>> self.manager_data
>>
>> persons_table = Table('persons', metadata,
>> Column('person_id', Integer, primary_key=True),
>> Column('name', String(50)),
>> Column('type', String(20), nullable=False)
>> )
>>
>> employees_table = Table('employees', metadata,
>> Column('person_id', Integer, ForeignKey('persons.person_id'),
>> primary_key=True),
>> Column('employee_data', String(50)),
>> Column('manager_data', String(50)),
>> )
>>
>> person_mapper = mapper(Person, persons_table, \
>> polymorphic_on=persons_table.c.type,
>> polymorphic_identity='person')
>> employee_mapper = mapper(Employee, employees_table, inherits=Person,
>> polymorphic_identity='engineer')
>> manager_mapper = mapper(Manager, inherits=employee_mapper,
>> polymorphic_identity='manager')
>>
>> metadata.create_all(engine);
>> Session = scoped_session(sessionmaker(bind=engine, autoflush=True,
>> transactional=True))
>> session = Session();
>>
>> session.save(Person('fer'))
>> session.save(Employee('e', 'e1'))
>> session.save(Manager('m', 'e2', 'm1'))
>> session.flush()
>>
>>
>>
>>>
>
>
> >
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