Question

While delving into ruby’s nested models I encountered an issue.

Consider the following scenario,

I have the following models:

• Author
• Book

With the following specifications:

Author:

class Author < ActiveRecord::Base
  attr_accessible :name
  has_many :books, dependent: :destroy

  accepts_nested_attributes_for :books #I read this is necessary here: http://stackoverflow.com/questions/12300619/models-and-nested-forms

  # and some validations...
end

Book:

class Book < ActiveRecord::Base
  attr_accessible :author_id, :name, :year
  belongs_to :author

  #and some more validations...
end

I would like to add a book to an author. Here is my authors_controller:

def new_book
  @author = Author.find(params[:id])
end

def create_book
  @author = Author.find(params[:id])
  if @author.books.create(params[:book]).save
    redirect_to action: :show
  else
    render :new_book
  end
end

And this is the form with which I try doing it:

<h1>Add new book to <%= @author.name %>'s collection</h1>
<%= form_for @author, html: { class: "well" } do |f| %>
    <%= fields_for :books do |b| %>
        <%= b.label :name %>
        <%= b.text_field :name %>
        <br/>
        <%= b.label :year %>
        <%= b.number_field :year %>
    <% end %>
    <br/>
    <%= f.submit "Submit", class: "btn btn-primary" %>
    <%= f.button "Reset", type: :reset, class: "btn btn-danger" %>
<% end %>

Problem:
When I type in the data and click “submit” it even redirects me to the correct author, but it doesn’t save a new record for that author.
After a lot of research I can’t seem to find what I am doing wrong here.

Answer 1

Change authors_controller to:

def new_book
  @author = Author.find(params[:id])
  @book = Book.new
end

Your form to:

<h1>Add new book to <%= @author.name %>'s collection</h1>
<%= form_for ([@author, @book]), html: { class: "well" } do |f| %>

And, routes.rb

resources :authors do
  resources :books
end