# File lib/dm-core/model/relationship.rb, line 48
      def relationships(repository_name = default_repository_name)
        # TODO: create RelationshipSet#copy that will copy the relationships, but assign the
        # new Relationship objects to a supplied repository and model.  dup does not really
        # do what is needed

        @relationships[repository_name] ||= if repository_name == default_repository_name
          Mash.new
        else
          relationships(default_repository_name).dup
        end
      end