问题描述
我正在从外部 API 中提取一些数据,并希望在本地缓存结果.我有一个 class SearchTerm
,我想通过表 searchable_items
将它与几个不同的 ActiveRecord 类型相关联.我很确定我的表格设置正确,但我的关联中一定有问题.
I'm pulling some data from an external API and would like to cache the results locally. I have a class SearchTerm
, which I would like to be associated with a few different ActiveRecord types through the table searchable_items
. I'm pretty sure I have the tables set up correctly, but something in my associations must be wrong.
class Foo < ActiveRecord::Base
has_many :search_terms, :as => :searchable, :through => :searchable_items
end
class Bar < ActiveRecord::Base
has_many :search_terms, :as => :searchable, :through => :searchable_items
end
class SearchTerm < ActiveRecord::Base
has_many :searchables, :through => :searchable_items
end
class SearchableItem < ActiveRecord::Base
belongs_to :search_term
belongs_to :searchable, :polymorphic => true
end
我希望能够执行类似 SearchTerm.find_by_term('SearchTerm').searchables
的操作(并且它会返回一个 Foo 和 Bar 对象数组)但是,我收到了错误在模型 SearchTerm 中找不到关联:searchable_items
I would expect to be able to do something like SearchTerm.find_by_term('SearchTerm').searchables
(and it would return an array of Foo and Bar objects) however, I get the errorCould not find the association :searchable_items in model SearchTerm
预先感谢您提供给我的任何见解!
Thanks in advance for any insight you can provide to me!
推荐答案
您需要将 has_many :searchable_items
关联添加到 Foo
, Bar
和 SearchTerm
模型,因为 :through =>:searchable_items
选项指的是该关联.
You need to add has_many :searchable_items
association to Foo
, Bar
and SearchTerm
models because :through => :searchable_items
option refers to that association.
http://guides.rubyonrails.org/association_basics.html#the-has_many-through-关联
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