Ruby on rails 有许多通过：、多态和自引用

我有一个带有三个模型的标签系统：人物、标签和标签

我想能够标记人物和标签，所以标记标签

人物和标签的模型似乎是正确的：

class Person < ActiveRecord::Base

 #associations
 has_many :taggings, as: :taggable
 has_many :tags, through: :taggings

end


class Tagging < ActiveRecord::Base

 attr_accessible :taggable_id, :taggable_type

 #associations
  belongs_to :tag
  belongs_to :taggable, polymorphic: true

 end

这适用于Person，其中SQL搜索标记id：

---

关于如何标记标签的想法将不胜感激！谢谢。

标记模型中未定义标记。您是否尝试过Have_多：taggings和Have_多：taggings，如：：taggable？

class Tag < ActiveRecord::Base
  attr_accessible :name

  has_many :taggings
  has_many :tags, through: :taggings, source: :taggable, source_type: :'Tag'

  has_many :people, through: :taggings, source: :taggable, source_type: :'Person'

end

Tag.find(10).tags
Tag Load (0.4ms)  SELECT `tags`.* FROM `tags` WHERE `tags`.`id` = 10 LIMIT 1
Tag Load (0.4ms)  SELECT `tags`.* FROM `tags` INNER JOIN 
 `taggings` ON `tags`.`id` = `taggings`.`taggable_id` 
  WHERE `taggings`.`tag_id` = 10 AND `taggings`.`taggable_type` = 'Tag'

Person.find(:last).tags
Person Load (0.4ms)  SELECT `people`.* FROM `people` ORDER BY `people`.`id` DESC LIMIT 1
Tag Load (0.4ms)  SELECT `tags`.* FROM `tags` INNER JOIN `taggings` ON 
 `tags`.`id` = `taggings`.`tag_id` WHERE `taggings`.`taggable_id` = 3 
 AND   `taggings`.`taggable_type` = 'Person'