Editing multiple models in one form

Rails
1

I’m looking to try and get the edit function working on a page for
editing multiple models within the one form.

I can currently edit any child models of a parent if the child records
already exist, the problem lies with adding extra child records to the
parent record.

My update function currently looks like this:

def update
@script = Script.find(params[:id])
if params[:script_metadatas]
params[:script_metadatas].each_with_index do |value, index|
script_metadata =
@script.script_metadatas.find_or_initialize_by_id(params[:script_metadatas][index.to_s]
? params[:script_metadatas][index.to_s][‘id’] : nil)
if script_metadata.new_record?
@script.script_metadatas.create(params[:script_metadatas][index.to_s])
else
script_metadata.update_attributes(params[:script_metadatas][index.to_s])
end
end
end
end
end

My view is such:

<% form_tag :action => ‘update’, :id => @script do %>


<% @script.script_metadatas.each_with_index do |script_metadata,
index| %>
<%= render :partial => ‘script_metadata_fields’, :locals => {
:script_metadata => script_metadata, :index => script_metadata.id } %>
<% end %>


<%= render :partial => ‘add_script_metadata_link’, :locals => {
:index => @script.new_script_metadata_id } %>




<%= submit_tag ‘Update Metadata Info’ %>

<% end %>

My ‘script_metadata_fields’ partial:

<% fields_for "script_metadatas[#{index}]", script_metadata do |f| %>    Key: <%= f.text_field :meta_key %> Value: <%= f.text_field :meta_value %> <%= link_to_remote 'Remove', :url => { :action => 'remove_script_metadata', :index => index } %> <% end %>

The problem i have is when i submit the data, i get the following error
message:

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.[]

All the correct parameters seem to be being passed, however the update
fails on the line beginning ‘params[:script_metadatas].each_with_index
do |value, index|’ in my controller action, and the line immediately
following it.

Can anyone suggest why?