Mongoid::Includes

Mongoid::Includes improves eager loading in Mongoid, supporting polymorphic associations, and nested eager loading.

Usage

Album.includes(:songs).includes(:musicians, from: :band)

Band.includes(:albums, with: ->(albums) { albums.gt(release: 1970) })

# The library supports nested eager loading using :from for terseness,
# but you can manually include nested associations using the :with option.
released_only = ->(albums) { albums.where(released: true) }
Musician.includes(:band, with: ->(bands) { bands.limit(2).includes(:albums, with: released_only) })

Pro Tip

Since you can modify the queries for the associations, you can use only and make your queries even faster:

Band.includes :musicians, with: ->(musicians) { musicians.only(:id, :name) }

Advantages

Avoid N+1 queries and get better performance.
No boilerplate code is required.
Modify the queries for related documents at will.

Installation

Add this line to your application's Gemfile and run bundle install:

  gem 'mongoid_includes'

Or install it yourself running:

gem install mongoid_includes

License

Copyright (c) 2015 Máximo Mussini

Permission is hereby granted, free of charge, to any person obtaining
a copy of this software and associated documentation files (the
"Software"), to deal in the Software without restriction, including
without limitation the rights to use, copy, modify, merge, publish,
distribute, sublicense, and/or sell copies of the Software, and to
permit persons to whom the Software is furnished to do so, subject to
the following conditions:

The above copyright notice and this permission notice shall be
included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.