Created: 2014-05-19 14:29
Updated: 2015-05-22 12:23
License: mit


Code Climate Build Status

This simple gem lets you find embedded documents easily. It does not instantiate parent record with a whole bunch of embedded documents. Instead it instantiates found embedded documents first and then sets parent association.

At the moment it allows you to find only one embedded document and assumes relation embeds_many.


Add this line to your application's Gemfile:

gem 'mongoid_embed_finder'

And then execute:

$ bundle

Or install it yourself as:

$ gem install mongoid_embed_finder


Let's say that you have defined two classes as follows:

class Door
  include Mongoid::Document
  embedded_in :car

class Car
  include Mongoid::Document
  embeds_many :doors
  field :name, type: String

Now you can easily retrieve instances of Door class using finder:

finder =, :car)
# first argument is embedded class
# second is name of the association to the parent

If you have door_id at your hands:

finder.first(id: door_id)
# => instance of Door class or nil in case not found

If you have door_id and car_id as well, you can narrow scope of cars:

finder.first(id: door_id, parent: { id: car_id })
# => instance of Door class or nil in case not found

In general you can basically pass any set of child's and parent's attributes. Latter group should be passed under parent key. Those attributes are passed down to Mongoid::Criteria.


If your embedded object has other referenced entities they will not be loaded.

By default no parent's attributes are set except its primary key. It is deliberate to limit amount of returned data. To retrieve parent's attributes list them under parent.include_fields as follows:

finder.first(id: door_id, parent: { id: car_id, include_fields: [:name] })


  1. Fork it ( )
  2. Create your feature branch (git checkout -b my-new-feature)
  3. Commit your changes (git commit -am 'Add some feature')
  4. Push to the branch (git push origin my-new-feature)
  5. Create a new Pull Request
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