Nested attributes are not updating in rails - ruby-on-rails

Question

I have 3 models:
class DropShipOrderLineItem < ActiveRecord::Base
belongs_to :drop_ship_order
belongs_to :line_item
validates_associated :drop_ship_order
validates_associated :line_item
validates :drop_ship_order_id, :presence => true
validates :line_item_id, :presence => true
attr_accessible :missing
end
class DropShipOrder < ActiveRecord::Base
attr_accessible :line_items, :line_items_attributes, :orders, :order_attributes
belongs_to :retailer
belongs_to :order
belongs_to :shipping_method
has_many :drop_ship_order_line_items
has_many :line_items, :through => :drop_ship_order_line_items
has_many :shipments, :dependent => :destroy
accepts_nested_attributes_for :line_items
accepts_nested_attributes_for :order
accepts_nested_attributes_for :drop_ship_order_line_items
before_create :generate_order_number
scope :by_number, lambda {|number| where("drop_ship_orders.number = ?", number)}
scope :between, lambda {|*dates| where("drop_ship_orders.created_at between ? and ?", dates.first.to_date, dates.last.to_date)}
scope :by_customer, lambda {|customer| joins(:order).joins(:user).where("users.email =?", customer)}
scope :by_state, lambda {|state| where("state = ?", state)}
scope :complete, where("drop_ship_orders.completed_at IS NOT NULL")
scope :incomplete, where("drop+ship_orders.orders.completed_at IS NULL")
make_permalink :field => :number
validates_associated :order
validates_associated :retailer
end
LineItem.class_eval do
has_one :drop_ship_order_line_item, :dependent => :destroy
has_one :drop_ship_order, :through => :drop_ship_order_line_items
accepts_nested_attributes_for :drop_ship_order_line_item
attr_accessible :drop_ship_order_line_item
# def missing
# self.drop_ship_order_line_item.missing
# end
end
View #1:
<div data-hook="admin_order_edit_form">
<div id="order-form-wrapper">
<%= render :partial => 'form', :locals => {:drop_ship_order => #drop_ship_order} %>
</div>
</div>
View form:
<%= form_for(#drop_ship_order, :url => admin_drop_ship_order_path(#drop_ship_order), :html => { :method => :put}) do |f| %>
<%= f.hidden_field :number %>
<table class="index">
<tbody id='line-items'>
<tr data-hook="admin_order_form_line_items_headers">
<th><%= t('item_description') %></th>
<th class="price"><%= t('price') %></th>
<th class="qty"><%= t('qty') %></th>
<th class="total"><span><%= t('total') %></span></th>
<th class="orders-actions" data-hook="admin_order_form_line_items_header_actions"></th>
</tr>
<%= f.fields_for :line_items do |li_form| %>
<%= render :partial => "admin/drop_ship_orders/line_item", :locals => { :f => li_form } %>
<% end %>
</tbody>
<tbody id='subtotal' data-hook="admin_order_form_subtotal">
<tr id="subtotal-row">
<td colspan="3"><b><%= t('subtotal') %>:</b></td>
<td class="total"><span><%= number_to_currency #drop_ship_order.item_total %></span></td>
<td></td>
</tr>
</tbody>
view line_item:
<tr id="<%= dom_id(f.object) %>" data-hook="admin_order_form_line_item_row">
<td width="300"><%=f.object.variant.product.name%> <%= "(" + variant_options(f.object.variant) + ")" unless f.object.variant.option_values.empty? %></td>
<td valign="top" class="price"><%= number_to_currency f.object.price %></td>
<td valign="top" class="qty"><strong><%= f.object.quantity %></strong></td>
<td valign="top" class="total"><%= number_to_currency (f.object.price * f.object.quantity)%></td>
<td data-hook="admin_order_form_line_item_actions">
<!--<input type="checkbox" name="apple" id="apples"/>-->
<%#= f.object.drop_ship_order_line_item.missing %>
<%= f.fields_for :drop_ship_order_line_item do |build|%>
<%= build.check_box :missing, :type => "checkbox" %>
<% end %>
</td>
</tr>
The :missing attribute is not being updated, and I just can't figure out why! Although the checkboxe is correctly being ticked if I manually change the values in my SQL table.
p.s: I just posted the relevant parts of my code.

Answer 1

In your LineItem model change attr_accessible :drop_ship_order_line_item to attr_accessible :drop_ship_order_line_item_attributes.

Answer 2

What is the :type => "checkbox" for in the following code:
<%= build.check_box :missing, :type => "checkbox" %>
The second parameter for the check_box form helper should be the method. I think if you change to the following code, it should work:
<%= build.check_box :missing %>