um yeah, actually this behavior is affecting all multi-level usage of "polymorphic_union". So, while polymorphic_union is quite obviously (since nobody has noticed this pretty glaring issue) on the decline in the 0.5 series, this is quite severe and ill try to have a look at it today.
On Dec 3, 2008, at 4:06 AM, Gaetan de Menten wrote: > Hello all, > > I've been playing a bit with polymorphic concrete inheritance, and > noticed that when you have several levels of "polymorphic" loading (ie > my child class is also a parent class which I want to load > polymorphically), the query for the top-level class includes the child > polymorphic join while I don't see any reason to (its table is already > contained in the parent join). See attached example. > > class A(object): > ... > > class B(A): > pass > > class C(B): > pass > > The query ends up something like: > > SELECT [all_columns] FROM ([pjoin_abc]), ([pjoin_bc]) > > Am I using it wrong, or is this a bug? > > -- > Gaëtan de Menten > http://openhex.org > > > > from sqlalchemy import * > from sqlalchemy.orm import * > > metadata = MetaData() > metadata.bind = 'sqlite:///' > > a_table = Table('a', metadata, > Column('id', Integer, primary_key=True), > Column('data1', String(20)) > ) > b_table = Table('b', metadata, > Column('id', Integer, primary_key=True), > Column('data1', String(20)), > Column('data2', String(20)) > ) > c_table = Table('c', metadata, > Column('id', Integer, primary_key=True), > Column('data1', String(20)), > Column('data2', String(20)), > Column('data3', String(20)) > ) > > metadata.create_all() > > class A(object): > def __init__(self, **kwargs): > for k, v in kwargs.iteritems(): > setattr(self, k, v) > > class B(A): > pass > > class C(B): > pass > > pjoin_all = polymorphic_union({ > 'a': a_table, > 'b': b_table, > 'c': c_table > }, 'type', 'pjoin') > > pjoin_bc = polymorphic_union({ > 'b': b_table, > 'c': c_table > }, 'type', 'pjoin_bc') > > > a_m = mapper(A, a_table, > with_polymorphic=('*', pjoin_all), > polymorphic_on=pjoin_all.c.type, > polymorphic_identity='a') > b_m = mapper(B, b_table, > inherits=a_m, concrete=True, > with_polymorphic=('*', pjoin_bc), > polymorphic_on=pjoin_bc.c.type, > polymorphic_identity='b') > c_m = mapper(C, c_table, > inherits=b_m, concrete=True, > polymorphic_identity='c') > > Session = sessionmaker() > session = Session() > > a1 = A(data1='a1') > b1 = B(data1='b1', data2='b1') > c1 = C(data1='c1', data2='c1', data3='c1') > > session.add(a1) > session.add(b1) > session.add(c1) > session.commit() > > metadata.bind.echo = True > > session.query(A).all() > print "*" * 20, "B", "*" * 20 > session.query(B).all() > --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
