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Welcome to the vivace-graph-v3 wiki!

VivaceGraph is an open source graph database written in pure Common Lisp.

VG takes design inspiration from CouchDB, neo4j and AllegroGraph. It implements an ACID-compliant object graph model with user-defined indexes and map-reduce views. It also implements a master / slave replication scheme for redundancy and horizontal read scaling. Querying the graph is accomplished via a number of Lisp methods or via a Prolog-like query language.

It currently only works with SBCL versions >= 1.045 and Clozure CL, though it would not take much work to port it to other Common Lisp implementations. A port to ECL has been started and can be found in the ecl-port branch.

Basic usage:

(ql:quickload :graph-db)
(use-package :graph-db)

(defvar *graph-name* :test-graph)
(defvar *graph-path* "/var/tmp/test-graph/")
(log:config :all :sane :d :nopretty :thread :daily "/var/tmp/graph.log")

;;; Types
(defun email-p (x)
  (and (stringp x)
       (find #\@ x)
       x))
(deftype email () `(satisfies email-p))

;;; Schema
(def-vertex person ()
  ((first-name :type string)
   (middle-name :type string)
   (last-name :type string))
  :test-graph)

(def-vertex customer (person)
  ((email :type email))
  :test-graph)

(def-vertex product ()
  ((name :type string)
   (upc :type string))
  :test-graph)

(def-vertex merchant ()
  ((name :type string))
  :test-graph)

(def-edge likes ()
 ()
 :test-graph)

(def-edge sells ()
 ()
 :test-graph)

(setq *graph* (make-graph *graph-name* *graph-path*))

;;; Indexes
;; This will index both customers and people
(def-view last-name :lessp (person :test-graph)
  (:map
   (lambda (person)
     (when (last-name person)
       (yield (last-name person) nil)))))

;; This will only index customers
(def-view email :lessp (customer :test-graph)
  (:map
   (lambda (customer)
     (when (email customer)
       (yield (email customer) nil)))))

;; Example of a map-reduce view
(def-view popularity :greaterp (likes :test-graph)
  (:map
   (lambda (like-edge)
     (yield (string-id (to like-edge)) 1)))
  (:reduce
   (lambda (keys values)
     (declare (ignore keys))
     (apply '+ values))))


(defun lookup-people-by-last-name (last-name)
  (let ((people (invoke-graph-view 'person 'last-name :key last-name)))
    (if people
        (mapcar (lambda (person)
                  (lookup-vertex (cdr (assoc :id person))))
                people)
        nil)))

(defun lookup-customer-by-email (email)
  (let ((customers (invoke-graph-view 'customer 'email :key email)))
    (if customers
        (lookup-vertex (cdr (assoc :id (first customers))))
        nil)))

;;; Add some data
(with-transaction ()
  (let ((c1 (make-customer :first-name "Joe" :last-name "Blow" :email "[email protected]"))
        (c2 (make-customer :first-name "Jill" :last-name "Blow" :email "[email protected]"))
        (m1 (make-merchant :name "Snake Oil, Inc."))
        (p1 (make-product :name "Oil of Longevity" :upc "1234567890"))
        (p2 (make-product :name "Oil of Slipperiness" :upc "abcdefghijk")))
    (make-sells :from m1 :to p1)
    ;; The above is equivalent to
    ;; (make-edge 'sells m1 p1 1 nil)
    (make-sells :from m1 :to p2)
    (make-likes :from c1 :to p1 :weight 100.0)
    (make-likes :from c1 :to p2 :weight 20.0)
    (make-likes :from c2 :to p2 :weight 50.0)))

;;; Now run some queries
(lookup-customer-by-email "[email protected]")

(lookup-people-by-last-name "Blow")

(select (:flat nil)
        (?liker ?product)
        (likes ?liker ?product))

(select (:flat nil :limit 1 :skip 0)
        (?liker ?product ?how-much)
        (likes ?liker ?product ?how-much))

(select-flat (?customer) (is-a ?customer customer))

(let ((person (select-one (?person) (is-a ?person person))))
  (declare (special person))
  (destructuring-bind (product like-qty)
      (select (:flat t :limit 1 :skip 0)
              (?product ?like-qty)
              (lisp ?person person) ;; Import the person into Prolog
              (likes ?person ?product ?like-qty))
    (format nil "~A likes '~A' with a degree of ~F"
            (first-name person)
            (name product)
            like-qty)))

(map-reduced-view (lambda (key id value)
                    (declare (ignore id))
                    (let ((product (lookup-vertex key)))
                      (cons product value)))
                  'likes
                  'popularity
                  :collect-p t)

(map-vertices (lambda (person)
                (format t "~A is a person~%" person)
                person)
              *graph*
              :collect-p t
              :vertex-type 'person)

(map-edges (lambda (edge)
             (let ((how-much (weight edge))
                   (product (lookup-vertex (to edge))))
               (cons product how-much)))
           *graph*
           :collect-p t
           :edge-type 'likes
           :vertex (lookup-customer-by-email "[email protected]")
           :direction :out)

;; Modifying a node requires copying and then saving that node. 
;; (save ...) returns the new revision of the node.
(with-transaction ()
  (let ((customer (copy (lookup-customer-by-email "[email protected]"))))
    (setf (middle-name customer) "Tim")
    (setq customer (save customer))))

(close-graph *graph*)

(setq *graph* (open-graph *graph-name* *graph-path*))
...
(close-graph *graph*)