ActiveNode

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This gem is not actively maintained anymore. Consider migrating to https://github.com/neo4jrb/neo4j.

ActiveNode is object graph mapping layer for neo4j deployed as standalone server. It is implemented on top of neography by Max De Marzi.

If you use neo4j in embedded mode with JRuby please refer to the Neo4j.rb gem at https://github.com/andreasronge/neo4j by Andreas Ronge.

Installation

Gemfile

Add active_node to your Gemfile:

gem 'active_node'

In case of default neo4j installation no further configuration is required. Otherwise refer to https://github.com/maxdemarzi/neography for further configuration options.

Usage

ActiveNode is inspired by ActiveRecord, but it implements only some of its features and if necessary provides some extensions to work with a graph database.

Creating and Retrieving Nodes

class Client < ActiveNode::Base
end

client = Client.create! name: 'Abc' # Creates a neo4j node with label Client and property 'name' == 'Abc'
client = Client.find client.id
client[:name] # 'Abc'
client[:name] = 'Abc Inc.'
client.save

Client.all # returns array of all clients
Client.find_by_cypher('match (c:Client) where c.name = {name}', name: 'Abc') # array of all Clients meeting given criteria

Declared Attrribues

class Client < ActiveNode::Base
  attribute :name, type: String #typed
  attribute :code #untyped
  attribute :keywords # leave array attributes untyped
  timestamps # will automatically add and maintain created_at and updated_at
end

client.name = 'Abc'
client.keywords = ['finance', 'investment']

Validation

Validation is similar to ActiveModel e.g.

validates :name, presence: true

Association

There are 2 types of associations: has_many and has_one. With additional options they can cover all possible relationships between nodes.

# label, class name, relationship type are derived from the association name, direction is by default outgoing
has_one :user # node with label User connected with outgoing relationship of type 'user'
has_many :users # multiple nodes with label User connected with outgoing relationship of type 'user'
# all option customized
has_one :father, type: :child, direction: :incoming, class_name: "Person"

The association declarations generate readers and writers.

Client.create!(name: 'Abc', users: [User.create!, User.create!])
Client.create!(name: 'Abc', user_id: User.create!.id)
...
client.user_ids = [user1.id, user2.id]
save
client.users # [user1, user2]

Custom Label

class Client < ActiveNode::Base
  def label
    'Company'
  end
end

Instances of Client will correspond to nodes with label Company.

More

ActiveNode works nicely with neography. If at any point you need more control or want to leverage some advanced features of the neo4j REST API you can easily take advantage of the lower layer calls.

Please create a new issue if you are missing any important feature in active_node.

In case of any questions don't hesitate to contact me at [email protected]