source: trunk/playground/versioned-pointer.lisp

;;+-----------------------------------------------------------------------------
;;+  Isidorus
;;+  (c) 2008-2010 Marc Kuester, Christoph Ludwig, Lukas Georgieff
;;+
;;+  Isidorus is freely distributable under the LLGPL license.
;;+  You can find a detailed description in trunk/docs/LLGPL-LICENSE.txt and
;;+  trunk/docs/LGPL-LICENSE.txt.
;;+-----------------------------------------------------------------------------

(asdf:operate 'asdf:load-op 'elephant)
(elephant:open-store '(:BDB "data_base"))
(defpclass Relation()
           ((to-a :associate NodeA
                  :accessor to-a
                  :initarg :to-a)
            (to-b :associate NodeB
                  :accessor to-b
                  :initarg :to-b)
            (version :initarg :version
                     :accessor version
                     :type integer
                     :index t))
           (:index t))
(defpclass NodeA()
           ((relation-to-b :associate (Relation to-a)
                           :accessor relation-to-b
                           :initarg :relation-to-b))
           (:index t))
(defpclass NodeB()
           ((relation-to-a :associate (Relation to-b)
                           :accessor relation-to-a
                           :initarg :relation-to-a))
           (:index t))
(defvar *rel* (make-instance 'Relation
                                      :to-a (make-instance 'NodeA)
                                      :to-b (make-instance 'NodeB)
                                      :version 1))