Question

I have a model named Order and another model named Member and when I try to display fields from the Members model in my Orders view it doesn’t even show when using the fields_for tag. Heres what my code looks like.

order model

class Order < ActiveRecord::Base
  has_many :members 
end

member model

class Member < ActiveRecord::Base
  belongs_to :order
end

orders controller

class OrdersController < ApplicationController

  def new
    @order = Order.new
    3.times { @order.members.build }
    @title = "Order Form"
  end

  def create
    @order = Order.new params[:order]
    if @order.save 
      flash[:notice] = "Your order has been created"
      redirect_to orders_path
    else
      @title = "Order Form"
      render 'new'
    end
  end 
end

The issue is in my orders view:

<% for member in @order.members %>
  This displays 3 times but the information below doesn't
  <% fields_for "...", member do |member_form| %>
    <p>
      Name: <%= member_form.text_field :name %>
    </p>
  <% end %>
<% end %>

For some odd reason the information in the fields for tag won’t even display once. Am I missing something?

If you find out what I am doing wrong, can you please explain it to me because I am new to rails.

Thanks in advance!

Answer 1

The block given to a fields_for call on a collection will be repeated for each instance in the collection, essentially creating its own loop, so you don’t really need to write your own explicit loop “for member in @order.members”. Further, you can leverage nested_attributes functionality to enable saving of associated members directly with @order.save:

class Order < ActiveRecord::Base
  has_many :members 
  accepts_nested_attributes_for :members
end

class Member < ActiveRecord::Base
  belongs_to :order
end

In the view:

<%= form_for @order do |order_form| %>
  ...
  <%= order_form.fields_for :members do |member_form| %>
    Name: <%= member_form.text_field :name %>
  <% end %>
<% end %>

And I think your controller create method should work as you have it.

See the API docs for fields_for, especially the One-to-many subsection.