The Crate adapter for ActiveRecord.
Installation
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
Usage
When using Rails update your database.yml
development:
adapter: crate
host: 127.0.0.1
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
private
def set_id
self.id = SecureRandom.uuid
end
end
Special Data Types
Array
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)")
Object
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}(https://github.com/crate/crate/commit/16a3d4b3f23996a327f91cdacef573f7ba946017).
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 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.
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}
Migrations
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
Gotchas
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.
Tests
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
Contributing
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.
Maintainer
License & Copyright
see LICENSE for details.