Question

我的标记系统包含三个模型：Person (People)，Tag和Tagging。

我希望能够标记人物和标签（因此标记标签）

Person和Tagging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

所以我能够<Person_instance>.tags并获得正确的标签。

问题来自于标签。我尝试了以下方法：

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

通过此设置，标签仍然可以标记其他标签，但模型会翻转标记的标签。例如，如果我在搜索Tag.id == 10的标签，那么SQL应该搜索taggable_id = 10，而不是tag_id，如下所示：

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'

这适用于Person，其中SQL搜索taggable_id：

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'

如何标记标签的想法将不胜感激！谢谢。

has_many through：，polymorphic和self-reference

0 个答案: