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The Crate adapter for ActiveRecord.


Note: 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

   adapter: crate
   port: 4200

Crate 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


  def set_id = SecureRandom.uuid


Special Data Types


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)")


Crate 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 a #dump and #load method on the class that creates a literal statement that is then used in the SQL. Read up more in this [commit}(

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]


Check out 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

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

Object Migrations

In the migrations you can create an object and specify the object behaviour(strict|dynamic|ignored) and it's 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 Crate. Issue #733

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


Crate 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!). Read more about it here

Crate does not support Joins (yet) so joins won't work.


Start up the crate server before running the tests

ruby spec/test_server.rb /path/to/crate

Then run tests with

bundle exec rspec spec


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.


##License & Copyright

see LICENSE for details.

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