> -----Original Message----- > From: sqlalchemy@googlegroups.com [mailto:sqlalchemy@googlegroups.com] > On Behalf Of Jules Stevenson > Sent: 16 June 2011 08:44 > To: sqlalchemy@googlegroups.com > Subject: [sqlalchemy] mapping a class linked with two other classes > (AttributeError: 'str' object has no attribute '_sa_instance_state') > > Hi List, > > I have a user class, a contact class, and a googleID class. > > the contact class has can have a googleID per user in the system. I'm > trying to map it out as follows: > > # ArkContact - clientprojectshot module > orm.mapper(ArkContact, contacts_table, properties={ > 'notes': orm.relation(ArkNote, > secondary=contact_notes_table, > backref='contacts', > single_parent=True, > cascade="all, delete, delete-orphan"), > 'users': orm.relation(ArkUser, > secondary=user_contact_table, > backref='contacts'), > 'google_UID': orm.relation(ArkUserContactGUID, > cascade="all, delete", > backref='user') > }) > > #user contact google_GUID > user_contact_UID = sa.Table('user_contact_UID_table', meta.metadata, > sa.Column('user_id', sa.types.Integer, sa.ForeignKey('users.id'), > primary_key=True), > sa.Column('contact_id', sa.types.Integer, > sa.ForeignKey('contacts.id'), primary_key=True), > sa.Column('google_UID', sa.types.String(length = 1024)) > ) > > class ArkUserContactGUID(object): > def __init__(self): > pass > > orm.mapper(ArkUserContactGUID, user_contact_UID) > > This raises two issues, the first is that an instrumented list is > returned for the google_UID paramter on the contact object, whereas > there should only ever be one (since as an operator there is only > ever > one user signed in - you). >
For one-to-one relationships, you should supply "uselist=False" to your relationship: http://www.sqlalchemy.org/docs/orm/relationships.html#one-to-one > The second is it outright errors :), presumably because my mapping is > off: > > File 'C:\\ark\\ark\\controllers\\contacts.py', line 368 in > initial_sync > contact_sync.initial_sync() > File 'C:\\ark\\ark\\arkTools\\arkGoogle.py', line 121 in initial_sync > self.add_contact_to_google(contact) > File 'C:\\ark\\ark\\arkTools\\arkGoogle.py', line 259 in > add_contact_to_google > data.google_UID.append(entry.get_id()) > File 'C:\\ark\\env_x64\\lib\\site-packages\\sqlalchemy-0.7.1- > py2.6.egg\\sqlalchemy\\orm\\collections.py', > line 952 in append > item = __set(self, item, _sa_initiator) > File 'C:\\ark\\env_x64\\lib\\site-packages\\sqlalchemy-0.7.1- > py2.6.egg\\sqlalchemy\\orm\\collections.py', > line 927 in __set > item = getattr(executor, 'fire_append_event')(item, _sa_initiator) > File 'C:\\ark\\env_x64\\lib\\site-packages\\sqlalchemy-0.7.1- > py2.6.egg\\sqlalchemy\\orm\\collections.py', > line 618 in fire_append_event > item, initiator) > File 'C:\\ark\\env_x64\\lib\\site-packages\\sqlalchemy-0.7.1- > py2.6.egg\\sqlalchemy\\orm\\attributes.py', > line 741 in fire_append_event > value = fn(state, value, initiator or self) > File 'C:\\ark\\env_x64\\lib\\site-packages\\sqlalchemy-0.7.1- > py2.6.egg\\sqlalchemy\\orm\\unitofwork.py', > line 35 in append > item_state = attributes.instance_state(item) > AttributeError: 'str' object has no attribute '_sa_instance_state' > > Many thanks for any help! > > Jules You're passing a string (presumably the result of entry.get_id()) where SA is expecting an instance of a mapped class. I haven't looked at your mapping in detail, but rather than this: data.google_UID.append(entry.get_id()) you probably want something like this: obj = ArkUserContactGUID(google_UID=entry.get_id()) data.google_UID.append(obj) (If I've misunderstood your mapping, these class names are probably wrong) Hope that helps, Simon -- 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.
