app/controllers/dynamic_select/clients_controller.rb
module DynamicSelect
class ClientsController < ApplicationController
respond_to :json
def trackings
@projects = Project.where(:client_id => params[:client_id])
@trackings = Tracking.where(:project_id => @projects.collect { |p| p.id }).select('id, description')
respond_with(@trackings)
end
end
end