Map Ruby Objects to Mongo Docs

class Person
  include Mongoid::Document
  field :name
  embeds_many :phones
  ...
end

class Phone
  include Mongoid::Document
  ...
end

Rich Criteria API

.all(:aliases => ["The Dude", ...])

.and(:age.gt => 18)

.excludes(:status => "Married")

.in(:status => ["Single", "Divorced"])

.where(:age.lte => 55)

Chainable Criteria & Named Scopes

Person
  .where(:last_name => "Zorg")
  .and(:middle_initial => "J")
  .and(:age.gt => 30)

class Player
  include Mongoid::Document
  field :status
  scope :inactive,
        :where => { :active => false }
end

Dead Simple Versioning

class Person
  include Mongoid::Document
  include Mongoid::Versioning
  ...
end

Callbacks

class Person
  include Mongoid::Document
  before_create :do_something
  after_destroy :do_something_else
  ...
end

Full Rails 3 Compatibility

# add this to config/application.rb
require 'mongoid/railtie'

>> rails generate mongoid:config
# generates config/mongoid.yml

>> script/rails generate model
# generates a mongoid model

Master/Slave support

# all reads go to slaves
class Person
  include Mongoid::Document
  enslave
end

# force a single query to use slaves
.where(:name => "Durran").enslave