Thanks Michael,
That worked great. I guess I missed that inheriting mappers don't
need a table/selectable/join to map to.
By the way, congrats on a great project. Your attention and effort
are clear in every aspect (including the unheard-of speed of support)!
On Sep 6, 3:04 pm, Michael Bayer <[EMAIL PROTECTED]> wrote:
> Maps to explicit joins are in any case going to integrate poorly with
> the joins created by SQLA's inheritance functionality. But in this
> case, no imitation of SQLA's join is needed:
>
> orm.mapper(Lab, inherits=Group,
> polymorphic_identity=u"group_lab",
> )
>
> On Sep 6, 2008, at 1:24 PM, Jason Yamada-Hanff wrote:
>
> > mport sqlalchemy as sa
> > from sqlalchemy import types as t
> > from sqlalchemy import orm
>
> > engine = sa.create_engine('sqlite:///:memory:', echo=True)
> > metadata = sa.MetaData()
>
> > agents = sa.Table('agents', metadata,
> > sa.Column('id', t.Integer,
> > sa.Sequence('agents_id_seq', optional=True),
> > primary_key=True),
> > sa.Column('type', t.Unicode(50),
> > sa.CheckConstraint("type IN ('agent', 'person', 'group',
> > 'group_org', \
> > 'group_lab', 'group_contactlist')"), nullable=False),
> > sa.Column('notes', t.UnicodeText),
> > )
>
> > groups = sa.Table('groups', metadata,
> > sa.Column('id', t.Integer, unique=True),
> > sa.Column('short_name', t.Unicode(50)),
> > sa.Column('name', t.Unicode(255), nullable=False),
> > sa.Column('group_status', t.Unicode(50),
> > sa.CheckConstraint("group_status IN ('active', 'not active',
> > 'closed')"),
> > default=u'active', nullable=False),
> > sa.Column('description', t.UnicodeText),
> > sa.PrimaryKeyConstraint('id'),
> > sa.ForeignKeyConstraint(['id'], ['agents.id'],
> > onupdate="CASCADE", ondelete="CASCADE")
> > )
>
> > class Agent(object):
> > pass
>
> > class Group(Agent):
> > pass
>
> > class Lab(Group):
> > pass
>
> > def map_agent_classes():
> > orm.mapper(Agent, agents,
> > polymorphic_on=agents.c.type,
> > polymorphic_identity=u"agent",
> > )
>
> > orm.mapper(Group, groups,
> > inherits=Agent,
> > polymorphic_identity=u"group",
> > )
>
> > lab_select =
> > agents.outerjoin(groups).select(agents.c.type==u'group_lab',\
> > use_labels=True).alias('labs')
> > orm.mapper(Lab, lab_select,
> > inherits=Group,
> > polymorphic_identity=u"group_lab",
> > )
>
> > map_agent_classes()
>
> > metadata.create_all(engine)
> > Session = orm.sessionmaker(bind=engine)
>
> > sess = Session()
>
> > lab = Lab()
> > lab.name = u"Lab Name"
> > lab.short_name = u"lab"
>
> > sess.add(lab)
> > sess.flush()
--~--~---------~--~----~------------~-------~--~----~
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
-~----------~----~----~----~------~----~------~--~---
