问题 Rails 4嵌套属性不保存

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。我尝试过同时使用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 %>

该调查可以很好地保存数据库，不会提出问题和答案。我看过我能找到的每一种资源，看起来我正确地做到了这一点，所以它真的让我发疯了。

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： 把我的新动作改成这样的事情：

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

成功了！

请参阅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 %>