CODEWITHSUNDEEP
rubymongodbmongoid
Iazel
Iazel

Reputation: 2336

Mongoid: Retrieves all embedded documents

Suppose we have these models:

class Person
  include Mongoid::Document

  embeds_many :albums
end

class Album
  include Mongoid::Document

  embeds_many :photos
end

class Photo
  include Mongoid::Document
end

What I want is to retrieves all Photo of a particular Person. Is there a mongoid/mongodb shortcuts or the only way is to iterate over person.albums and store all album.photos in a new array?

Thanks.

Upvotes: 3

Views: 1780

Answers (1)

Arthur Neves
Arthur Neves

Reputation: 12128

You have 2 ways to do this, one is through Mongoid, which, AFAIK, will inflate all objects. Something like:

Person.only("albums.photos").where(id: '1').albums.map(&:photos).flatten

Or you can do it in Moped(driver) which will return only an array of photos.

Person.collection.find(id: "1").select("albums.photos" => 1).
first["albums"].map { |a| a["photos"] }.flatten

On the DB load, both dont make any difference, as they will yield the same query, only difference is that the first one will create way more objects than the second one.

Upvotes: 4

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