Question

I’m really new to both ruby on rails and programming. I am trying to develop an application but i am stucked now. I was watching http://railscasts.com/episodes/196-nested-model-form-part-1 to make nested model forms but i am having an error. My problem details are as follows;

I have employers model, and employers model has_many interviews, and interview model has_many customquestions. I’m trying to create a form through which i will collect info to create interview. Although i made all necessary assosications, when i submit the form it raises error saying that “Customquestions interview can’t be blank”. I am kinda sure that it is because of that i miss some code in interview controller. Below you can see my interview controller and the form template that i am using to submit info.

Interview Controller

class InterviewsController < ApplicationController
  before_filter :signed_in_employer

  def create
    @interview = current_employer.interviews.build(params[:interview])

    if @interview.save
      flash[:success] = "Interview created!"
      redirect_to @interview
    else
      render 'new'
    end
  end

  def destroy
  end

  def show
    @interview = Interview.find(params[:id])
  end

  def new
    @interview = Interview.new
      3.times do
    customquestion = @interview.customquestions.build
     end
  end
end

Form which i use to submit info:

<%= provide(:title, 'Create a new interview') %>
<h1>Create New Interview</h1>

<div class="row">
  <div class="span6 offset3">
    <%= form_for(@interview) do |f| %>
    <%= render 'shared/error_messages_interviews' %>

      <%= f.label :title, "Tıtle for Interview" %>
      <%= f.text_field :title %>

      <%= f.label :welcome_message, "Welcome Message for Candidates" %>
      <%= f.text_area :welcome_message, rows: 3 %>

      <%= f.fields_for :customquestions do |builder| %>
        <%= builder.label :content, "Question" %><br />
        <%= builder.text_area :content, :rows => 3 %>
      <% end %>
      <%= f.submit "Create Interview", class: "btn btn-large btn-primary" %>
    <% end %>
  </div>
</div>

In interview model, i used accepts_nested_attributes_for :customquestions

Interview Model

class Interview < ActiveRecord::Base
  attr_accessible :title, :welcome_message, :customquestions_attributes
  belongs_to :employer
  has_many :customquestions
  accepts_nested_attributes_for :customquestions

  validates :title, presence: true, length: { maximum: 150 }
  validates :welcome_message, presence: true, length: { maximum: 600 }
  validates :employer_id, presence: true
  default_scope order: 'interviews.created_at DESC'
end

Answer 1

The validation error gets raised in the customquestions model because (I assume) it validates :interview_id. The problem is that interview_id won’t get set until the parent object (Interview) is saved, but validations for customquestion are run before Interview is saved.

You can let cusomtquestions know about this dependency by adding the option :inverse_of=> :customquestions to belongs_to :interview in the customquestions model.