Rails nested form edits - ruby-on-rails

Question

I am trying to figure out the whole nested form thing, and am having issues rending the form for editing.
I'm not doing this the "typical way" with a new and create action, because i'm not actually going to be saving anything. I'm just using this form to generate some tests.
Here is what I have..
model.rb
class Model < ActiveRecord::Base
has_many :columns
has_many :associations
accepts_nested_attributes_for :associations, :reject_if => lambda { |a| a[:type].blank? }
accepts_nested_attributes_for :columns, :reject_if => lambda { |a| a[:name].blank? }
attr_accessible :name, :associations_attributes, :columns_attributes
end
column.rb
class Column < ActiveRecord::Base
belongs_to :model
attr_accessible :db_index, :mass_assign, :max_length, :min_length, :name, :required, :unique, :columns_attributes
validates :name, :presence => true
end
generator_controller.rb
def model
if params['submit']
#model = Model.new(params[:model])
#model.columns.build
else
#model = Model.new
3.times { #model.columns.build }
end
render 'generator/model'
end
form view
<%= nested_form_for(#model, :url => '/model', :html => {:style => 'width:100%;'}) do |f| %>
<%= flash_helper() %>
<h3>Model Name</h3>
<%= f.text_field :name %>
<h3>Add Table Columns</h3>
<div id="columns">
<% f.fields_for :columns do |builder| %>
<div class="float_left column">
<%= builder.label :name %>
<br>
<%= builder.text_field :name, :size => 20 %>
</div>
<div class="float_left column">
<%= builder.label :mass_assign %>
<br>
<%= builder.check_box :mass_assign %>
</div>
<div class="float_left column">
<%= builder.label :required %>
<br>
<%= builder.check_box :required %>
</div>
<div class="float_left column">
<%= builder.label :unique %>
<br>
<%= builder.check_box :unique %>
</div>
<div class="float_left column">
<%= builder.label :db_index %>
<br>
<%= builder.check_box :db_index %>
</div>
<div class="float_left column">
<br>
<%= image_tag "delete-icon24x24.png", :class => "btnDel clickable" %>
</div>
<br class="clear_float">
<% end %>
<%= f.link_to_add image_tag('add-icon.png'), :columns %>
</div>
<br><br>
<input type="submit" name="submit">
<p>
<%= #results %>
</p>
<% end %>
So the problem is, the form when new is not displaying the columns that "3.times { #model.columns.build }" is supposed to do. Also, when I submit the form, I need to figure out why it is getting rid of all of those nested attributes that were added. So each time I submit the form, and it renders the form again, all the attributes are gone. (The "model" attributes are still there, but the "column" attributes reset each time)
Any ideas on what i'm doing wrong?
Thanks

Answer 1

I am embarrassed to even admit this, but hopefully it will help someone else with one more thing to check if they have the same problem.
<% f.fields_for :columns do |builder| %>
changed to:
<%= f.fields_for :columns do |builder| %>
Yeah.. can't believe I did that...