gistfile1.txt

# In DM 0.9.7 ...

class Test
  include DataMapper::Resource

  property :id,          Integer,  :serial => true
  property :parent_id,   Integer,  :index => true

  has_1  :child, :class_name => 'Test', :parent_key => [:id], :child_key => [:parent_id]
end

t = Test.new
t.save
t2 = Test.new(:parent_id => t.id)
t2.save
t.reload
t.child.child  # This *should* be nil, but comes out to the same as t.child