please see http://www.sqlalchemy.org/docs/05/mappers.html#adjacency-list-relationships wrt the "remote_side" option and proper configuration of the "many- to-one" side of a self-referential relationship.
On Feb 1, 2009, at 3:19 AM, n00b wrote: > > g'day, > > i wanted to give the adjacency pattern a try in the context of a dog > pedigree database and used > http://groups.google.com/group/sqlalchemy/browse_thread/thread/d78357121da8014a/537377ff73bdede7?lnk=gst&q=family+tree#537377ff73bdede7 > as a reference. > the requirement at hand is to be abe to go back, say, 4-5 generations > but i don't seem to be able to change the mapper to successively yield > parents. here's a bit of code to illustrate. > > persons = Table("persons", meta, > Column("person_id", Integer, primary_key=True), > Column("name", Unicode(40), nullable=False), > Column("mother_id", Integer, ForeignKey("persons.person_id")), > Column("father_id", Integer, ForeignKey("persons.person_id")) > ) > > > class Person(object):pass > > > mapper(Person, persons, properties={ > 'mom': relation(Person, > primaryjoin=persons.c.mother_id==persons.c.person_id,\ > backref='children_m', lazy=False, join_depth=4), > 'dad': relation(Person, > primaryjoin=persons.c.father_id==persons.c.person_id,\ > backref='children_f', lazy=False, join_depth=4) > }) > > #meta.drop_all() > meta.create_all() > > session = Session() > > gd_1= Person() > gd_1.name =u'grand dad 1' > session.add(gd_1) > session.commit() > > gm_1 = Person() > gm_1.name =u'grand ma 1' > session.add(gm_1) > session.commit() > > gd_2 = Person() > gd_2.name =u'grand dad 2' > session.add(gd_2) > session.commit() > > gm_2 = Person() > gm_2.name =u'grand ma 2' > session.add(gm_2) > session.commit() > > d_1 = Person() > d_1.name =u'dad' > d_1.mother_id = gm_1.person_id > d_1.father_id = gd_1.person_id > session.add(d_1) > session.commit() > > m_1 = Person() > m_1.name =u'mom' > m_1.mother_id = gm_2.person_id > m_1.father_id = gd_2.person_id > session.add(m_1) > session.commit() > > c = Person() > c.name = u'child' > c.mother_id = m_1.person_id > c.father_id = d_1.person_id > session.add(c) > session.commit() > > r = session.query(Person).filter(Person.name==u'child').one() > print u'name :', r.name > print u'mother, father id :', r.mother_id, r.father_id > print u'mother, father obj :', r.mom, r.dad > print u'backref children _m, _f :', r.children_m, r.children_f > print > > r = session.query(Person).filter(Person.dad.contains(d_1)).one() > print u'name :', r.name > print u'mother, father id :', r.mother_id, r.father_id > print u'mother, father obj :', r.mom, r.dad[0].name > print u'backref children _m, _f :', r.children_m, r.children_f[0].name > > session.close() > > as you can see, the current mapper yields the children, if any, (and > only on the paternal side. i'd greatly appreciate insights to a) get > the list of parents and b) to get both maternal and paternal > references. > > thx > > > > --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
