Activerecord rails通过关联属于\u

我在rails 3.0上，试图找出建立归属关系的正确方法：通过关系（我知道这是不可能的）。下面是一个例子：

class ParentCompany < ActiveRecord::Base
  has_many :subsidiaries
  has_many :employees, :through => :subsidiaries
end

class Subsidiary < ActiveRecord::Base
  belongs_to :parent_company
  has_many :employees
end

class Employee < ActiveRecord::Base
  belongs_to :subsidiary
  belongs_to :parent_company, :through :subsidiary # <-- I know this is invalid
end

类父公司：子公司
结束
class Subsidiary隶属于：母公司：：通过：子公司您可以使用
委托
来完成此任务，而无需使用关联

class Employee < ActiveRecord::Base
  belongs_to :subsidiary
  delegate :parent_company, to: :subsidiary
end

class Employee

class Employee < ActiveRecord::Base
  belongs_to :subsidiary
  delegate :parent_company, to: :subsidiary
end