Mongoid

The following code demonstrate how to add and update and destroy multiple embedded document.

 
require 'mongoid'

Mongoid.configure.master = Mongo::Connection.new.db('images')

class Image
  include Mongoid::Document
  embeds_many :words
  #lib/mongoid/nested_attributes.rb
  accepts_nested_attributes_for :words, :allow_destroy => true 
end

class Word
  include Mongoid::Document
  embedded_in :image

  field :text
end
     

image = Image.create
word100 = image.words.create :text => '100'
word200 = image.words.create :text => '200'

#normally, the params were post from browser
params = {
  :words => { 
    #lib/mongoid/relations/builders/nested_attributes/many.rb
    0 => {:id => word100.id, :text => '1000'},     #update
    #lib/mongoid/relations/nested_builder.rb
    1 => {:id => word200.id, :_destroy => true},   #destroy
    2 => {:text => '300'}                          #create

  }
}

#create and update action were taken, but destroy does not work
#image.update_attributes params
image.words_attributes = params[:words]
p image.reload.words