The Ruby on Rails ActiveRecord adapter for CrateDB, using the crate_ruby driver with HTTP connectivity.

Note: The activerecord-crate-adapter currently only works with Rails 4.1.x.

Add this line to your application's Gemfile:

gem 'activerecord-crate-adapter'

And then execute:

$ bundle

Or install it yourself as:

$ gem install activerecord-crate-adapter

When using Rails update your database.yml

 development:
   adapter: crate
   host: 127.0.0.1
   port: 4200

CrateDB doesn't come with an autoincrement feature for your model ids. So you need to set it yourself. One way is to use SecureRandom.uuid, if you think there is a better one, please add an issue, so we can discuss.

class Post < ActiveRecord::Base

  before_validation :set_id, on: :create

  private

  def set_id
    self.id = SecureRandom.uuid
  end

end

You can simply create Array columns by specifying t.array and passing array_type when you create a migration.

t.array :tags, array_type: :string
t.array :votes, array_type: :integer
t.array :bool_arr, array_type: :boolean

When you create an object just pass your Array directly

Post.create!(title: 'Arrays are awesome', tags: %w(hot fresh), votes: [1,2])
post = Post.where("'fresh' = ANY (tags)")

CrateDB allows you to define nested objects. I tried to make it as simply as possible to use and reuse existing AR functionality, I therefore ask you to reuse the existing serialize functionality. AR#serialize allows you to define your own serialization mechanism, and we simply reuse that for serializing an AR object. To get serialize working simply create #dump and #load methods on the class that creates a literal statement that is then used in the SQL. Read up more in this commit about array and object literals.

I tried to make your guys life easier and created a module that does this automatically for you. Simply make all attributes accessible and assign it in the initializer. So a serialized class should look like this:

require 'active_record/attribute_methods/crate_object'

class Address
  attr_accessor :street, :city, :phones, :zip

  include CrateObject

  def initialize(opts)
    @street = opts[:street]
    @city = opts[:city]
    @phones = opts[:phones]
    @zip = opts[:zip]
  end

end

Check out the CrateObject module if you need to write your own serializer.

Then in your model simply use #serialize to have objects working.

  class User < ActiveRecord::Base
    serialize :address, Address
  end

Note: I do not plan to support nested objects inside objects.

In the migrations, you can create an object, specify the object behaviour (strict|dynamic|ignored), and its schema.

t.object :address, object_schema_behaviour: :strict,
                   object_schema: {street: :string, city: :string, phones: {array: :string}, zip: :integer}

Currently, adding and dropping indices is not support by CrateDB, see issue #733.

# not supported by CrateDB yet
add_index :posts, :comment_count
remove_index :posts, :comment_count

CrateDB is eventually consistent, that means if you create a record, and query for it right away, it won't work (except queries for the primary key).

In this context, read more about the REFRESH TABLE statement.

See DEVELOP.md.

If you think something is missing, either create a pull request or log a new issue, so someone else can tackle it. Please refer to CONTRIBUTING.rst for further information.

• Crate.IO GmbH
• Christoph Klocker, @corck

This project is licensed under the Apache License 2.0.