On Sep 28, 2010, at 5:50 PM, Julien Iguchi-Cartigny wrote:
> Hi,
>
> I'm trying to declare a adjacency list as follow:
>
> class CourseSet(AbstractContainer):
> parent_id = Column('PARENT_COURSE_SET', Integer,
> ForeignKey('CM_MEMBER_CONTAINER_T.ENTERPRISE_ID'))
> children = relationship("CourseSet", backref=backref('parent',
> remote_side=AbstractNamed.eid))
OK sorry, you're really working the mixins to the Nth degree here. The
columns that are on CourseSet are relative to the mapped class. The Column()
object on AbstractNamed gets copied when declarative sees it. So the correct
column to place on "remote_side" would be AbstractContainer.eid, since
AbstractContainer is the class that's mapped to the table which contains
"ENTERPRISE_ID".
>
> @classproperty
> def __mapper_args__(self):
> args = dict()
> args.update(AbstractContainer.__mapper_args__)
> args.update({'polymorphic_identity':
> 'org.sakaiproject.coursemanagement.impl.CourseSetCmImpl'})
> return args
>
> But I couldn't succeed, i've the following error message:
>
> sqlalchemy.exc.ArgumentError: Relationship CourseSet.parent could not
> determine any local/remote column pairs from remote side argument
> set([Column('ENTERPRISE_ID', String(length=255, convert_unicode=False,
> assert_unicode=None, unicode_error=None,
> _warn_on_bytestring=False), )])
>
> I've tried to use
> http://www.sqlalchemy.org/docs/orm/relationships.html#adjacency-list-relationships
> but with no success. The only "not-classical" thing is the use of
> AbstractNamed.eid (a field from a parent class), is there an impact ?
>
> Cheers,
>
> Julien.
>
> PS: other parent objects:
>
> class AbstractPersistent(object):
> version = Column('VERSION', Integer)
> last_modified_by = Column('LAST_MODIFIED_BY', String(255))
> last_modified_date = Column('LAST_MODIFIED_DATE', Date)
> created_by = Column('CREATED_BY', String(255))
> created_date = Column('CREATED_DATE', Date)
>
> def __repr__(self):
> return "<AbstractPersistent('%s','%s', '%s','%s','%s')>" % \
> (self.version, self.last_modified_by,
> self.last_modified_date,
> self.created_by, self.created_date)
>
> class AbstractNamed(AbstractPersistent):
> eid = Column('ENTERPRISE_ID', String(255))
> title = Column('TITLE', String(255))
> description = Column('DESCRIPTION', String(255))
>
> def __repr__(self):
> return "<AbstractNamed('%s','%s', '%s')>" % \
> (self.eid, self.title, self.description) + \
> super(AbstractNamed, self).__repr__()
>
>
> class AbstractContainer(Base,AbstractNamed):
> __tablename__ = 'CM_MEMBER_CONTAINER_T'
> id = Column('MEMBER_CONTAINER_ID',Integer,primary_key=True)
> discriminator = Column('CLASS_DISCR', String(100))
> __mapper_args__ = {'polymorphic_on': discriminator }
>
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