ruby-on-rails - 无效的源反射宏 :has_many :through

Question

我有这样愤怒的联想:融资 >- 事件 >- 子程序 >- 程序。我想通过所有程序从程序中访问 last_financings，所以代码是:

class Fcp < Program
  has_many :fcp_subprograms,
           :foreign_key => 'parent_id'
  has_many :subprogram_last_actual_financings,
           :through => :fcp_subprograms,
           :source => :last_actual_financings

class FcpSubprogram < Program
  belongs_to :fcp,
             :class_name => 'Fcp',
             :foreign_key => 'parent_id'

  has_many :events,
           :foreign_key => 'fcp_id'

  has_many :last_actual_financings,
           :through => :events,
           :source => :last_actual_financings

class Event < ActiveRecord::Base
  belongs_to :fcp,
             :class_name => 'Fcp',
             :foreign_key => 'fcp_id'
  belongs_to :fcp_subprogram,
             :class_name => 'FcpSubprogram',
             :foreign_key => 'fcp_id'

  has_many :last_actual_financings,
           :class_name => 'ActualFinancing',
           :order => 'date DESC',
           :limit => 1

所以当我想在 after_initialize 函数中访问 subprogram_last_actual_financings 时，我得到了这个错误

Invalid source reflection macro :has_many :through for has_many :subprogram_last_actual_financings, :through => :fcp_subprograms.  Use :source to specify the source reflection.

但我的关联中有 :source 选项。我做错了什么？

Answer 1

你得到的错误是关于 source_reflection 是一个无效的关联，因为 has_many through 的 source 必须是 belongs_to、has_one 或 has_many without through 选项。所以你不能使用 :last_actual_financings 作为来源。