问MongoID关系查询

EN

class State
  include Mongoid::Document
  field :name    
  embeds_many :cities
end


class City
  include Mongoid::Document    
  field :name
  field :zip_code    
  embedded_in :state    
  references_many :organization_addresses
end

class Organization
  include Mongoid::Document    
  field :name    
  references_many :organization_addresses
end

class OrganizationAddress
  include Mongoid::Document    
  field :address
  field :latitude, :type=>Float
  field :longitude, :type=>Float    
  referenced_in :organization
  referenced_in :city
end