Welcome to Neo4j.rb

Neo4j.rb is a graph database for JRuby.

You can think of Neo4j as a high-performance graph engine with all the features of a mature and robust database. The programmer works with an object-oriented, flexible network structure rather than with strict and static tables — yet enjoys all the benefits of a fully transactional, enterprise-strength database.

It uses two powerful and mature Java libraries:

Documentation

Why Neo4j.rb or a Graph Database ?

Here are some of the major benefits of Neo4j.rb

Some Examples

Neo4j::Node

Example of creating a Neo4j::Node

require "rubygems"
require 'neo4j'

Neo4j::Transaction.run do
  node = Neo4j::Node.new (:name => 'andreas')
  node.outgoing(:friends) << Neo4j::Node.new (:name => 'peter')
  node.outgoing(:friends).each {|node| puts "name #{node[:name]}"}
end

Neo4j::NodeMixin

Example of mapping a ruby class to a node and delaring properties and relationships and lucene index.

class Person
  include Neo4j::NodeMixin
  property :name
  property :city

  has_n :friends
  has_one :address
  index :name
end

# assume we have an transaction already running
andreas = Person.new (:name => 'andreas')
andreas.friends << Person.new (:name => 'peter')
andreas.friends.each {|person| puts "name #{person.name}" }
Person.find("name: andreas").first.name # => 'andreas'

Neo4j::Rails::Model

Example of using Neo4j with Rails 3 (ActiveModel)

class User < Neo4j::Model
  attr_accessor :password
  attr_accessible :email, :password, :password_confirmation, :pending_account

  after_save   :encrypt_password

  email_regex = /\A[\w+\-.]+@[a-z\d\-.]+\.[a-z]+\z/

  property :email
  index :email

  has_one(:avatar).to(Avator)

  validates :email, :presence => true,:format   => { :with => email_regex }
  validates :email, :uniqueness => true, :unless => :pending_account?
  accepts_nested_attributes_for :avatar, :allow_destroy => true

  ...
end

Generate a Rails Application

Example of creating an Neo4j Application from scratch: (make sure you have installed JRuby version >= 1.6.2)

gem install rails
rails new myapp -m http://andreasronge.github.com/rails3.rb
cd myapp
bundle
rails generate scaffold User name:string email:string
rails s
open a webbrowser: http://localhost:3000/users

To run it with Tomcat instead of WEBrick

gem install trinidad
trinidad

Architecture

As you seen above, neo4j.rb consists of a three layers API:

Notice that you can always access the lower layers if you want to do some more advanced. You can even access the Java API directly.

Presentation Materials and other URLs

Project information

Contributing

Development configuration

Have you found a bug, need help or have a patch ? Just clone neo4j.rb and send me a pull request or email me. Do you need help - send me an email (andreas.ronge at gmail dot com).

License