Creating Variable Number of Models in One Form (Page 5 of 7)

Try going back to what you had in your earlier post, where education_histories was on its own parameter: "education_histories[#{index}]" instead of "resume[education_histories][#{index}]"

Also, I made some edits to my previous post so try following that in order to get the address working properly.

Are you looping through the education_histories parameter in the create action in your controller?

# in create action
params[:education_histories].each_value { |education_history| @resume.education_histories.build(education_history) }

Solution for multiple models on one form with nested collections and nested objects.

I got things working and the short is that it doesn't seem that (1.1.6) Rails likes creating nested collections with nested objects in them from form values. While I love Rails, I don't see why this is an issue. But I suppose as long as there's a work around, I'm cool with that and hopefully this helps others that might run into this issue.

My form is a resume form where a user can have multiple education histories and each education history can have one address. The address partial is common both to the resume object as well as the nested education history objects.

I have, as one would expect, the form broken up into multiple partials, each one wrapping their specific model. So there's an _address partial for all address objects used on the form as well as a _education_histories partial, which renders the _address partial. Also I may note that the education histories are Ajax based, so I can add/remove a history w/out forcing a page reload.

Models:

class Resume < ActiveRecord::Base
  has_one :address
  has_and_belongs_to_many :education_histories
end
class EducationHistory < ActiveRecord::Base
  has_and_belongs_to_many :resumes
  has_one :address
    
  def address_attr=(attributes)
    build_address if address.nil?
    address.attributes = attributes
  end
end
class Address < ActiveRecord::Base
  belongs_to :resume
  belongs_to :education_history
end

class ResumeController < ApplicationController
  
  def new
    @resume = Resume.new
    @resume.education_histories << EducationHistory.new(:address=>Address.new)
    @resume.address = Address.new
  end
  def create
    @resume = Resume.new(params[:resume])
    params[:education_histories].each_value { |history| @resume.education_histories.build(history) }
    if @resume.save
     render :action => 'success'
    else
     render :action => 'resume'
    end
  end
  
  def add_education_history # Ajax
    @resume = Resume.new(params[:resume])
    params[:education_histories].each_value { |history| @resume.education_histories.build(history) }
    @resume.education_histories << EducationHistory.new(:address=>Address.new)
    render :partial => 'education_history'
  end
  
  def remove_education_history # Ajax
    @resume = Resume.new(params[:resume])
    params[:education_histories].each_value { |history| @resume.education_histories.build(history) }
    @resume.education_histories.pop
    render :partial => 'education_history'    
  end
  
end

resume.rhtml

<% form_for :resume, @resume, :url => { :action => "create" }, 
:html => {:name=>'resume_form',:id=>'resume_form'} do |@resume_form| %>
<p>Resume title:<br/><%= @resume_form.text_field :title %></p>
<p>Your address:<br/>
<% fields_for :address, @resume.address do |@address_fields| %>
<%=render :partial => 'address'%>
<%end%><p>
<div id="education_history"><%= render :partial=>"education_histories" %></div>
<% end -%>

...
<% # Ajax add/remove education history links %>
<% if @resume.education_histories.length < 11 %><%= link_to_remote 'Add education history',
:update=>'education_history', :url => { :action =>'add_education_history' },  
:with => "Form.serialize($('resume_form'))" %>
<% end %>
<% if @resume.education_histories.length > 1 %> | 
<%= link_to_remote 'Remove last education history',
:update=>'education_history', :url => { :action =>'remove_education_history' }, 
 :with => "Form.serialize($('resume_form'))" %>
<%end%>
<%# end Ajax links %>
<% @resume.education_histories.each_with_index do |education_histories,index| %>
<% fields_for "education_histories[#{index}]", education_histories do |education_histories_fields| %>
<p>Highest degree:<br/><%= education_histories_fields.text_field :highest_degree %></p>
  <% fields_for "education_histories[#{index}][address_attr]", 
  @resume.education_histories[index].address do |@address_fields| %> 
  <%= render :partial => 'address'%>
  <%end -%>
<%end -%>
...

...
<p>Street 1:<br/><%= @address_fields.text_field :street_1 %>
<p>Street 2:<br/><%= @address_fields.text_field :street_2 %>
...

problems now are:

1) when i save the first/main model i notice that in the second/associated model table there is always a row filled with NULL values and i suppose that is so because we create an empty second model at the beginning of the create action.

2)if the all form don't pass some validation and it is redisplayed to the user, i see that it is added one more second model field even if i don't click the add_secondmodel ajax link

waiting for a response of the problems above by the author of the tutorial i would like to add another issue. How is the best approach to build the equivalent edit page?

Try replacing this:

params[:tasks].each_value { |task| @project.tasks.build(task) }

params[:tasks].sort.each { |index, task| @project.tasks.build(task) }

i'm still there with the edit code, my only problem is when i remove a second model "in the middle" and then i submit the edit form: Rails throws an error that says:
You have a nil object when you didn't expect it!
You might have expected an instance of Array.
The error occurred while evaluating nil.[]

if instead i remove second models in order it doesn't happen.
my code is the following for the action:

def edit_enterprise
    @banks = Bank.find(:all, :order => "nome").map {|b| [b.nome, b.id] }
    @customer = Customer.find(params[:id])
    if request.post?
      if params[:contacts]
        params[:contacts].each_with_index do |value, index|
          if params[:contacts][index.to_s]['id'] == ''
            @customer.contacts.create(params[:contacts][index.to_s])
          else
            @customer.contacts.find_by_id(params[:contacts][index.to_s]['id']).update_attributes(params[:contacts][index.to_s])
          end
        end
      end
     
       if !params[:customer][:sede_legale].blank?
          if params[:adress_check][:domifisc_check] == "1"
            params[:customer][:domi_fisc] = params[:customer][:sede_legale]
          end
          if params[:adress_check][:indfatt_check] == "1"
            params[:customer][:ind_fatt] = params[:customer][:sede_legale]
          end
          if params[:adress_check][:indmerce_check] == "1"
            params[:customer][:ind_merce] = params[:customer][:sede_legale]
          end
        end
     
      if @customer.update_attributes(params[:customer])
        flash[:notice] = 'Cliente aggiornato con successo'
        redirect_to :action => 'index'
      end
    end
   
  end

Last edited by skyblaze (2007-08-28 09:28:32)

You need to go through the form builder when generating the field so it gives it the proper name.

<%= f.collection_select :priority_id, Priority.find(:all), :id, :name %>

Great tutorial. Thanks, man.