
Traversing Domain Heirarchies
-----------------------------

A common use case when handling object relational mappings to the URL space,
is allowing traversal of foreign key relation ships, and maintaining the 
fk variant when creating new objects.

Constraints
-----------

Managed Container traversal is currently incompatible with sqlalchemy relation
properties, as its spec'd on the domain class where a mapper property would be
placed. A future revision may try to encapsulate this layer into a traversal
adapter.

these aren't always exposed at the fk:

  >> from ore.alchemist import Session
  >> import transaction
  >> tim_burton = Director("tim burton")
  
  >> scissorhands = Movie("Edward Scissorhands")
  >> scissorhands.director = tim_burton
  >> session.save( scissorhands, tim_burton )
  >> transaction.commit()
  
  >> tim_burton.movies.keys()
  movie-1
  
  >> tim_burton.movies.values()['title']
  'Edward Scissorhands'
  
