Ruby on rails dropdown box

Question

I just wrote my first ruby on rails application and I'm kinda stuck. I have a library database with authors, books and categories. a book belong to an author and category. SO now when creating a book I would like to select an author and category from a list. How do I go about doing that. I'm new on ruby so any help would be appreciated. For now the book only has the name column.

Here is the books class or model:

class Book < ActiveRecord::Base
  belongs_to :author
  belongs_to :category
  attr_accessible :name
  validates :name, :presence => true
end

Answer 1

In your books form use following select field as:

<%= f.select :author_id, Author.all.collect {|p| [ p.name, p.id ] } %>
<%= f.select :category_id, Category.all.collect {|p| [ p.name, p.id ] } %>

For more details of association alse see http://guides.rubyonrails.org/association_basics.html

Answer 2

It likely be something like in your view:

<% form_for :book do |f|%>
 <% f.text_field :name %>
 <% f.select :author_id, options_for_select( @authors.all.map{|a| a.name, a.id } %>
 <% f.select :category_id, options_for_select( @categories.all.map{|c| c.name, c.id} ) %>
<% end %>

and something like

@authors = Author.all
@categories = Category.all

in your controller