如何在一个模型中触发多个counter_cache作为has_many:through

Question

我有3个模型(Allen, Bob, Chris)，它们与Join模型是多态的。和一个连接到join模型的User模型。

class Allen < ActiveRecord::Base
  has_many :joins, :as => :resource
  ...
end
class Bob < ActiveRecord::Base
  has_many :joins, :as => :resource
  ...
end
class Chris < ActiveRecord::Base
  has_many :joins, :as => :resource 
  ...
end
class Join < ActiveRecord::Base
  belongs_to :initiator, :class_name => "User", :foreign_key => "user_id"
             :counter_cache => "How to write with 3 different counter cache?"
  belongs_to :resource, :polymorphic => true, :counter_cache => :resources_count
end
class User < ActiveRecord::Base
  has_many :joins
  has_many :allens, :through => :joins, :source => :initiator
  has_many :initial_joins, :class_name => "Join"
end

我的问题是如何在用户模型中为Bob, Chris和Allen编写计数器缓存

或者你可以在这里查看:https://gist.github.com/1350922

Answer 1

我认为，没有标准的方法来实现这一点。在您的Allen, Bob和Chris中添加after_create回调，您将获得与此特定Bob相关的所有User的列表，并手动重新计算bobs_count。