Sending the details of the multi form to the database - ruby-on-rails

Question

I have to create a form which includes Batches and Samples.
General idea would be Batches having (received:date, group_leader:string, contact_person:string, batch_comment:string and num_of_samples:integer) .
N.B batches have many samples.
now the Samples include ( sample_name, species, sample_type, ini_conc, ini_vol, and sample_comment).
Now as these are of one to many relationships, I have created a form after following many tutorials having a page showing batch detail entry as well as asking for how many samples it involved in each batch. After the user types in (for eg. 3), the form generates three fields having sample details (also including name, species, type, conc, vol, etc.) but I was not able to send these details to the database.
The only thing that updates the database is one sample information.
my view looks something like this :
New sample:
<p><% form_for(sample) do |f| %></p>
<p><% (1..#batch.sample_no).each do |i| -%></p>
<%= f.error_messages %>
<p>
<%= f.hidden_field :batch_id %>
</p>
<p>
<%= f.label :sample_name %><br />
<%= f.text_field :sname %>
</p>
<p>
<%= f.label :organism %><br />
<%= f.text_field :organism, :rows => 2 %>
</p>
<p>
<%= f.label :sample_type %><br />
<%= f.select(:samp_type, %w{ DNA RNA}) %>
</p>
<p>
<%= f.label :ini_conc %><br />
<%= f.text_field :ini_conc %>
</p>
<p>
<%= f.label :ini_vol %><br />
<%= f.text_field :ini_vol %>
</p>
<p>
<%= f.label :storage_space %><br />
<%= f.text_field :storage_space %>
</p>
<p>
<%= f.label :samp_comment %><br />
<%= f.text_area :samp_comment, :rows => 3 %>
</p>
<% end -%>
<p><%= f.submit 'Submit' %></p>
<% end %>
I haven't done anything much with my controller. (in fact I have no idea which controller I should add codes to) meaning I have created two scaffolds, one for batch and one for samples and I have made a partial of the samples_view_new.html.erb and saved it in the batch_view folder which gives me an opportunity to add samples in the show_html.erb of the batch.
my models of batch.rb and sample.rb look some thing like this
<p>class Batch < ActiveRecord::Base</p>
<p>has_many :samples</p>
<p>end</p>
<p>class Sample < ActiveRecord::Base </p>
<p>belongs_to :batch</p>
<p>end</p>

Answer 1

if I understand your requirements correctly, you're searching for nested forms as excellently described by Ryan Bates at railscasts.com
Tutorial 1: Nested Model Form Part 1
Tutorial 2: Nested Model Form Part 2
Here is some more help for you:
In your Bash model
has_many :samples
accepts_nested_attributes_for :samples
Your Bash Controller will have at least 2 actions: new and create
In your new action:
#bash = Bash.build
4.times { #bash.samples.build } # where 4 is the no. of samples, could also be param[:amount] in case you add a preliminary action with a form and an amount field, but I suggest using javascript as described in Tutorial 2 above for better user experience
In the create action:
#bash = Bash.new(params[:bash]) # you now have access to #bash.samples
if #bash.save ...
And finally the "new" view:
<%= form_for #bash do |f| %>
<%= f.text_field :group_leader %> <!-- ... -->
<%= f.fields_for :samples do |builder| %>
<%= builder.text_field :sample_name %> <!-- ... -->
<% end %>
<%= end %>
With this and the tutorials you should now be able to build a killer app for your degree's application. Good luck!

Answer 2

I think I have the solution to the problem...
My main idea was to send multiple rows in the database at once... so just follow this tutorial
http://www.stephenchu.com/2008/03/paramsfu-3-using-fieldsfor-and-index.html