I don't like to have attributes added to classes on the fly, but the back_populates keyword mentioned in your link seem to have solved it. Still don't understand why the relationship worked with George but not with Martha. Thanks a million for your though help Michael.
On Thursday, April 17, 2014 11:12:17 AM UTC-7, Michael Bayer wrote: > > you want to link “relationships” and “source” using a backref, so that the > reference is updated both directions without doing a database round trip. > > See > http://docs.sqlalchemy.org/en/rel_0_9/orm/relationships.html?highlight=backrefs#linking-relationships-with-backref. > > > > On Apr 17, 2014, at 1:04 PM, Mats Nordgren <mats.n...@gmail.com<javascript:>> > wrote: > > class Person(Entity): > '''A person.''' > > __tablename__ = 'people' > > id = Column(Integer, ForeignKey('entities.id'), primary_key=True) > > first_name = Column(String(50)) > middle_name = Column(String(50)) > last_name = Column(String(50)) > > date_of_birth = Column(Date) > date_of_death = Column(Date) > > relationships = relationship('Relationship', > foreign_keys='relationships.c.source_id') > > __mapper_args__ = { > 'polymorphic_identity': 'person'} > > Missed the mapper args part of person. > > > On Thursday, April 17, 2014 10:02:54 AM UTC-7, Mats Nordgren wrote: >> >> class Entity(Base): >> '''A base for entities.''' >> >> __tablename__ = 'entities' >> >> id = Column(Integer, Sequence('entity_id_seq'), primary_key=True) >> type = Column(String(50)) >> >> tax_id = Column(String(20)) >> >> memberships = relationship('Membership') >> >> __mapper_args__ = { >> 'polymorphic_identity': 'entity', >> 'polymorphic_on': type} >> >> class Person(Entity): >> '''A person.''' >> >> __tablename__ = 'people' >> >> id = Column(Integer, ForeignKey('entities.id'), primary_key=True) >> >> first_name = Column(String(50)) >> middle_name = Column(String(50)) >> last_name = Column(String(50)) >> >> date_of_birth = Column(Date) >> date_of_death = Column(Date) >> >> relationships = relationship('Relationship', >> foreign_keys='relationships.c.source_id') >> >> class Relationship(Base): >> '''A relationship.''' >> >> __tablename__ = 'relationships' >> >> source_id = Column(Integer, ForeignKey('people.id'), >> primary_key=True) >> target_id = Column(Integer, ForeignKey('people.id'), >> primary_key=True) >> relationship_type_id = Column(Integer, ForeignKey(' >> relationship_types.id'), primary_key=True) >> >> from_date = Column(Date) >> thru_date = Column(Date) >> >> notes = Column(Text) >> >> source = relationship('Person', foreign_keys=source_id) >> target = relationship('Person', foreign_keys=target_id) >> relationship_type = relationship('RelationshipType', >> foreign_keys=relationship_type_id) >> >> class RelationshipType(Base): >> '''A relationship type.''' >> >> __tablename__ = 'relationship_types' >> >> id = Column(Integer, Sequence('relationship_type_id_seq'), >> primary_key=True) >> >> description = Column(String(50)) >> >>> >>> > -- > You received this message because you are subscribed to the Google Groups > "sqlalchemy" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to sqlalchemy+...@googlegroups.com <javascript:>. > To post to this group, send email to sqlal...@googlegroups.com<javascript:> > . > Visit this group at http://groups.google.com/group/sqlalchemy. > For more options, visit https://groups.google.com/d/optout. > > > -- You received this message because you are subscribed to the Google Groups "sqlalchemy" group. To unsubscribe from this group and stop receiving emails from it, send an email to sqlalchemy+unsubscr...@googlegroups.com. To post to this group, send email to sqlalchemy@googlegroups.com. Visit this group at http://groups.google.com/group/sqlalchemy. For more options, visit https://groups.google.com/d/optout.
