rails mongodb implementation

rails + mongoid

References: https://github.com/mongodb/mongoid

mongoid is one of the best ODMs

Install mongodb - Reference: https://docs.mongodb.com/manual/tutorial/install-mongodb-on-ubuntu/

Ruby and Ruby on Rails version-
  Rails - 5+
  Ruby  - 2.5+


Steps to start with mongoid -

Gemfile
  gem 'mongoid'


Configuration
  rails g mongoid:config
  this command will create a file config/mongoid.yml

  add following line into application.rb
  Mongoid.load! "./config/mongoid.yml"
  # defines mongodb configraion just like database.yml


  Change inside mongoid.yml
  specify database name and related credentials
  mongodb by default run on port: 27017


An example with model user

Create your model under app/models - user.rb
------------------
class Role
  include Mongoid::Document

  field :name, type: String, default: ""

  # index on name
  index({ name: 1 }, {name: "role_name_index" })
end
------------------

------------------
class User
  include Mongoid::Document

  field :balance, type: BigDecimal, default: 0.0
  field :age, type: Integer, default: 0
  field :name, type: String, default: 0
  field :data, type: Hash, default: {}

  # association
  belongs_to :role

  # index on role_id
  index({ role_id: 1 }, {name: "user_role_index" })
end
------------------


belongs_to :role
  if you define association it will automatically creates associationName_id (ex: role_id)

index({ role_id: 1 }, {name: "user_role_index" })
  Adding index on role_id in ascending order


The collection would be created if does not exist - (pluralized and camle case version of model name - (users)) at the time of any operation like create / update.

Some readymade rake jobs
How to create index
  rake db:mongoid:create_indexes
How to remove index
  rake db:mongoid:remove_indexes



Finally create indexes
  rake db:mongoid:create_indexes


now its ready -

rails console
  > Role.create(name: 'admin')

  > User.create({name: 'cherry', age: 28, balance: 10.34, data: {}.to_json, role: Role.find_by(name: 'admin')})