Rails 4嵌套属性不保存

Question

我似乎无法获得嵌套属性来保存到数据库.我正在使用Rails 4.

这是我的模特:

class Answer < ActiveRecord::Base
  belongs_to :question
end


class Question < ActiveRecord::Base
  has_many :answers
  belongs_to :survey
  accepts_nested_attributes_for :answers, allow_destroy: true
end

class Survey < ActiveRecord::Base
  has_many :questions
  validates_presence_of :name
  accepts_nested_attributes_for :questions
end

这是控制器:

def create

  @survey = Survey.new(survey_params)

  respond_to do |format|
    if @survey.save
      format.html { redirect_to @survey, notice: 'Survey was successfully created.' }
      format.json { render action: 'show', status: :created, location: @survey }
    else
      format.html { render action: 'new' }
      format.json { render json: @survey.errors, status: :unprocessable_entity }
    end
  end
end

def survey_params
  params.require(:survey).permit(:name, questions_attributes:[:content, :id, :survey_id, 
    answers_attributes:[:content, :id, :questions_id]
    ])
end

最后,这是表单本身.我尝试过使用f.fields_for和fields_for

<%= form_for(@survey) do |f| %>
  <% if @survey.errors.any? %>
    <div id="error_explanation">
      <h2><%= pluralize(@survey.errors.count, "error") %> prohibited this survey from being saved:</h2>

      <ul>
      <% @survey.errors.full_messages.each do |msg| %>
        <li><%= msg %></li>
      <% end %>
      </ul>
    </div>
  <% end %>

  <div class="field">
    <%= f.label :name %><br>
    <%= f.text_field :name %>
  </div>

  <%= f.fields_for :question do |builder| %>
     <%= builder.label :content %>
     <%= builder.text_area :content %>

       <%= f.fields_for :answer do |builder| %>
         <%= builder.label :content, "Answer" %>
         <%= builder.text_field :content %>
       <% end %>

  <% end %>
  <div class="actions">
    <%= f.submit %>
  </div>
<% end %>

调查可以很好地保存数据库,不会提出问题和答案.我已经查看了我能找到的所有资源,看起来我正确地做到了这一点,所以这真的让我发疯了.

这个例子只是一个快速的脚手架,所以我有一些代码要粘贴,但我似乎无法让它在其他任何地方工作.

编辑:将我的新动作更改为以下内容:

def new
  @survey = Survey.new
  @survey.questions.build
end

成功了!

请寻求解决方案以获得解决方案

这是我正在使用的新表单,仍然只保存调查名称

  <%= f.fields_for :question do |question_builder| %>
  <%= form_for(@survey) do |f| %>
  <% if @survey.errors.any? %>
    <div id="error_explanation">
      <h2><%= pluralize(@survey.errors.count, "error") %> prohibited this survey from being saved:</h2>

      <ul>
      <% @survey.errors.full_messages.each do |msg| %>
        <li><%= msg %></li>
      <% end %>
      </ul>
    </div>
  <% end %>

  <div class="field">
    <%= f.label :name %><br>
    <%= f.text_field :name %>
  </div>

  <%= f.fields_for :question do |question_builder| %>
   <%= question_builder.label :content %>
   <%= question_builder.text_area :content %>

   <%= question_builder.fields_for :answer do |answer_builder| %> 
       <%= answer_builder.label :content, "Answer" %>
       <%= answer_builder.text_field :content %>
   <% end %>

<% end %>

  <div class="actions">
    <%= f.submit %>
  </div>
<% end %>

Answer 1

看起来你正在使用错误的表单构建器对象.将问题部分更改为以下内容:

<%= f.fields_for :question do |question_builder| %>
   <%= question_builder.label :content %>
   <%= question_builder.text_area :content %>

   <%= question_builder.fields_for :answer do |answer_builder| %> 
       <%= answer_builder.label :content, "Answer" %>
       <%= answer_builder.text_field :content %>
   <% end %>

<% end %>

本来你使用f表单生成器的线f.fields_for :answers...,但是鉴于你的模型代码,因为它是一个Question是accepts_nested_attributes_for一个Answer,我们只是交换表单生成器对象用于一个question部分.

注意:为清楚起见,我更改了构建器对象的名称.

更新

为了构建这样一个深层嵌套的关系,你必须遍历你的"构建"关联(questions在这种情况下),并build再次调用它的has_many关联.所以关闭gabrielhilal的答案,你会这样做:

def new
  @survey = Survey.new
  @survey.questions.build
  @survey.questions.each do |question|
      question.answers.build
  end
end

请注意,在您的情况下,由于您只是明确地创建了一个问题,因此您可以在技术上改为执行此操作(而不是循环):

@survey.questions.first.answers.build

免责声明:如果有更清洁,更多的Rails-y,这样做的方式,我很遗憾没有意识到这一点.