两个belongs_to关联的相同模型

Question

我有一个模型,PointOfContact其中has_many Systems.从Systems侧面我想要识别PointOfContact为technical_manager或project_manager(或两者).虽然仍然只PointOfContact在DB中保留1次.

我的尝试如下:

class System < ActiveRecord::Base
  belongs_to :project_manager, :class_name => 'PointOfContact'
  belongs_to :technical_manager, :class_name => 'PointOfContact'
end

class PointOfContact < ActiveRecord::Base
  has_many :systems
end

当我运行我的规范(示例如下)时,我可以正确地创建System联系点关联.但是,PointOfContact它并不知道它与System的关联.这是为什么？

@sys = System.create
@tm = PointOfContact.create
@pm = PointOfContact.create

@sys.project_manager = @pm
@sys.technical_manager = @tm

@pm.systems.should have(1).items #> expected 1 items, got 0

Answer 1

感谢jamesw在RailsForum.com:两个belongs_to协会的相同模型找到了解决方案.

class System < ActiveRecord::Base
  belongs_to :project_manager, :class_name => 'PointOfContact', :foreign_key => 'project_manager_id'
  belongs_to :technical_manager, :class_name => 'PointOfContact', :foreign_key => 'technical_manager_id'
end

class PointOfContact < ActiveRecord::Base
  has_many :project_managed_systems, :class_name => 'System', :foreign_key => 'project_manager_id'
  has_many :technical_managed_systems, :class_name => 'System', :foreign_key => 'technical_manager_id'
end