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.nordg...@gmail.com> 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+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. -- 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.
