Hello, I have recently converted a Pylons app from SQLObject to SQLAlchemy 0.3.10. Conversion went quite well.
I need to serialize access to some of my objects, so I've looked into extending MapperExtension as described at [1] to add a mutex on load. First, I define an extension and instantiate it: -------- from sqlalchemy.orm import MapperExtension import mutex class MutexExtension(MapperExtension): def create_instance(self, mapper, selectcontext, row, class_): self.mutex = mutex.mutex() return None mutexext = MutexExtension() ------- My mapper setup looks like this: switch_mapper = mapper (Switch, switch_table, extension=[mutexext.mutexext, sac.ext], properties={'ports':sqla.relation(SwitchPort)}) When I try to fetch objects from the database, I get a exception setting self.entity_name: Module sqlalchemy.orm.mapper:1485 in _instance << instance = self._create_instance(context.session) else: instance._entity_name = self.entity_name if self.__should_log_debug: self.__log_debug("_instance(): created new instance %s identity %s" % (mapperutil.instance_str(instance), %str(identitykey)))>> instance._entity_name = self.entity_name exceptions.AttributeError: 'NoneType' object has no attribute '_entity_name' What did I do wrong? Thanks, Ross [1] http://www.sqlalchemy.org/docs/03/adv_datamapping.html#advdatamapping_extending --~--~---------~--~----~------------~-------~--~----~ 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 [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~----------~----~----~----~------~----~------~--~---