How to handle multiple models in one rails form?

Question

I have the following models

class Survey < ActiveRecord::Base
  has_many :survey_sections
  accepts_nested_attributes_for :survey_sections
end

class Surv         


        

Answer 1

You can handle as many forms as you need, if you use the fields_for helper properly.

This is where you're falling short I think (your controller seems okay).

I also wrote an answer about this some time back.

#app/models/survey.rb
class Survey < ActiveRecord::Base
    has_many :sections
    accepts_nested_attributes_for :sections
end

#app/models/section.rb
class Section < ActiveRecord::Base
    belongs_to :survey
    has_many :questions
    accepts_nested_attributes_for :questions
end

#app/models/question.rb
class Question < ActiveRecord::Base
    belongs_to :section
    has_many :answers
end

Try and keep your model names as succinct as possible.

#app/controllers/surveys_controller.rb
class SurveysController < ApplicationController
   def new
      @survey = Survey.new
      @survey.sections.build.questions.build
   end

   def create
      @survey = Survey.new survey_params
      @survey.save
   end

   private 

   def survey_params
      params.require(:survey).permit(:title, sections_attributes: [:title, questions_attributes:[:title]])
   end
end

#app/views/surveys/new.html.erb
<%= form_for @survey do |f| %>
   <%= f.text_field :title %>
   <%= f.fields_for :sections do |section| %>
       <%= section.text_field :title %>
       <%= section.fields_for :questions do |question| %>
           <%= question.text_field :title %>
       <% end %>
   <% end %> 
   <%= f.submit %>
<% end %>

Answer 2

You can get best explanation here with same type of model

http://railscasts.com/episodes/196-nested-model-form-part-1

#app/models/survey.rb
class Survey < ActiveRecord::Base
    has_many :sections, :dependent => :destroy
    accepts_nested_attributes_for :sections, :allow_destroy => true
end

#app/models/section.rb
class Section < ActiveRecord::Base
    belongs_to :survey
    has_many :questions, :dependent => :destroy
    accepts_nested_attributes_for :questions, :allow_destroy => true
end

#app/models/question.rb
class Question < ActiveRecord::Base
    belongs_to :section
    has_many :answers
end

now in controller

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

Now in views

<%= form_for @survey do |f| %>
  <%= f.error_messages %>
  <p>
    <%= f.label :name %><br />
    <%= f.text_field :name %>
  </p>
  <%= f.fields_for :sections do |builder| %>
     <%= builder.text_field :title %>
     <%= builder.fields_for :questions do |question| %>
        <%=  question.text_field :content%>
     <% end %>
  <% end %>
  <p><%= f.submit "Submit" %></p>
<% end %>