在 Rails 中找不到关联问题 [英] Could not find the association problem in Rails

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问题描述

我是 Ruby on Rails 的新手,我显然有一个活动记录关联问题,但我无法自己解决.

I am fairly new to Ruby on Rails, and I clearly have an active record association problem, but I can't solve it on my own.

给定三个模型类及其关联:

Given the three model classes with their associations:

# application_form.rb
class ApplicationForm < ActiveRecord::Base
  has_many :questions, :through => :form_questions
end

# question.rb
class Question < ActiveRecord::Base
  belongs_to :section
  has_many :application_forms, :through => :form_questions
end

# form_question.rb
class FormQuestion < ActiveRecord::Base
  belongs_to :question
  belongs_to :application_form
  belongs_to :question_type
  has_many :answers, :through => :form_question_answers
end

但是当我执行控制器向申请表添加问题时,出现错误:

But when I execute the controller to add questions to application forms, I get the error:

ActiveRecord::HasManyThroughAssociationNotFoundError in Application_forms#show

Showing app/views/application_forms/show.html.erb where line #9 raised:

Could not find the association :form_questions in model ApplicationForm

谁能指出我做错了什么?

Can anyone point out what I am doing wrong?

推荐答案

在ApplicationForm 类中,需要指定ApplicationForms 与'form_questions' 的关系.它还不知道.在您使用 :through 的任何地方,您都需要先告诉它在哪里可以找到该记录.你的其他课程也有同样的问题.

In the ApplicationForm class, you need to specify ApplicationForms's relationship to 'form_questions'. It doesn't know about it yet. Anywhere you use the :through, you need to tell it where to find that record first. Same problem with your other classes.

所以

# application_form.rb
class ApplicationForm < ActiveRecord::Base
  has_many :form_questions
  has_many :questions, :through => :form_questions
end

# question.rb
class Question < ActiveRecord::Base
  belongs_to :section
  has_many :form_questions
  has_many :application_forms, :through => :form_questions
end

# form_question.rb
class FormQuestion < ActiveRecord::Base
  belongs_to :question
  belongs_to :application_form
  belongs_to :question_type
  has_many :form_questions_answers
  has_many :answers, :through => :form_question_answers
end

假设您就是这样设置的.

That is assuming that's how you have it set up.

这篇关于在 Rails 中找不到关联问题的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!

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