Example code tested on the mmconsole regarding http://groups.google.com/group/mongomapper/browse_thread/thread/74239f58e51042ef

associations_console_test.rb

class User
  include MongoMapper::Document

  def profile
    person.profile
  end

  one :person, :class_name => 'Person', :foreign_key => :owner_id
end


class Person
  include MongoMapper::Document
  
  key :email, String, :unique => true
  key :url, String
  key :owner_id, ObjectId
  
  belongs_to :owner, :class_name => 'User'
  one :profile, :class_name => 'Profile'
end


class Profile
  include MongoMapper::EmbeddedDocument
  
  key :first_name, String
  key :last_name, String
  key :image_url, String
end


my_user = User.create(:person => Person.new(:profile => Profile.new))
my_user.profile # => #<Profile _id: BSON::ObjectId('4edc555578fca28259000001')>