Welcome to MongoRecord


Note: MongoRecord is no longer supported by its authors. For a list of MongoDB object mappers, see is.gd/gdehy.

What MongoRecord was

MongoRecord is an ActiveRecord-like framework for MongoDB.

This document assumes you have read the MongoDB documentation.

A quick code sample:

require 'rubygems'
require 'mongo'
require 'mongo_record'

class Track < MongoRecord::Base
  collection_name :tracks
  fields :artist, :album, :song, :track
  index :artist

  def to_s
    "artist: #{artist}, album: #{album}, song: #@song, track: #{@track ? @track.to_i : nil}"

MongoRecord::Base.connection =

t = Track.new(:artist => 'Level 42', :album => 'Standing In The Light',
              :song => 'Micro-Kid', :track => 1)
puts "There are #{Track.count()} tracks."
t = Track.find(:first, :conditions => {:song => 'Micro-Kid'})
Track.find(:all, :sort => 'song').each { |t| puts t.to_s }


$ gem install mongo_record

MongoRecord depends on the Mongo Ruby Driver, version 0.20.1 or higher. Installing the MongoRecord gem will also install the Mongo Ruby Driver if you don't have it already.

The source code is available at github.com/mongodb/mongo-ruby-driver. You can either clone the git repository or download a tarball or zip file. Once you have the source, you can use it from wherever you downloaded it or you can install it as a gem from the source by typing

$ rake gem:install

Getting Started

See the examples, read the MongoRecord::Base and MongoRecord::Cursor documentation, and look at tests/test_mongo.rb.


You can use MongoRecord::Base or talk to the database (stored in the $db object) directly.

See MongoRecord::Base and MongoRecord::Cursor.


See MongoRecord::LogDevice. When running outside of the cloud (for example, during development), all log messages are echoed to $stderr which is normally the console.


Jim Mulholland, jim at squeejee dot com

  • Ability to save custom attributes not declared in the model

  • Save and retrieve custom “_id” fields

  • Find_each functionality

  • Find_last based on the created_at field

  • Assigning created_at and updated_at fields even if they are not declared

  • Alias methods for “first”, “last” and “all”

  • Fix for sum method

Clinton R. Nixon, crnixon at gmail dot com

  • Ability to define and query indexes from models

Nate Wiger, github.com/nateware

  • Optimization to first and last to close cursor and avoid expensive to_a

  • Implemented Model.update_all leveraging Mongo collection.update

  • Scoped dynamic finders to each instance, so rows with varying attributes work

  • Added row.attributes helper to enable use of ActiveRecord::Callbacks if desired

Camilo Lopez

  • Updates for later driver releases.