Rails: How do I make a form submit an array of records?

Question

I need to make a form that will submit an array of records. I am using rails 2.3.11 and trying to follow the instructions in the one to many section here: http://api.rubyonrails.org/v2.3.8/classes/ActionView/Helpers/FormHelper.html

However when I do it, I get errors, or the form only submits the last record in the array.

This doesn't work, because @query[:filters] is an array, so fields_for will throw an exception:

  <% form_for :aquery, @query, :url => {:action => 'index'} do |a| %>
    <% a.fields_for :filters, @query[:filters] do |f| %>
      <p>
        <%= f.select :field, @fields %>
        <%= f.select :logic, ["all", "is", "is not", "none"]%>
        <%= f.text_field :arg, :size => 30 %>
      </p>
    <% end %>
    <%= submit_tag l(:button_apply) %>
  <% end %>

This doesn't work because it ignores the contents of @query[:filters], and only renders one set of fields regardless of how large the array is:

    <% a.fields_for :filters do |f| %>

And this doesn't work because it will only submit the last item in the array:

<% form_for :aquery, @query, :url => {:action => 'index'} do |a| %>
  <% @query[:filters].each do |filter| %>
    <% a.fields_for :filters, filter do |f| %>
      <p>
        <%= f.select :field, @fields %>
        <%= f.select :logic, ["all", "is", "is not", "none"]%>
        <%= f.text_field :arg, :size => 30 %>
      </p>
    <% end %>
  <% end %>
  <%= submit_tag l(:button_apply) %>
<% end %>

Answer 1

You need to run over your filters and do the indexing manually.

<% form_for :aquery, @query, :url => {:action => 'index'} do |a| %>
  <% @query[:filters].each_with_index do |filter, i| %>
    <% a.fields_for :filters, filter, :index => i do |f| %>
      <p>
        <%= f.select :field, @fields %>
        <%= f.select :logic, ["all", "is", "is not", "none"]%>
        <%= f.text_field :arg, :size => 30 %>
      </p>
    <% end %>
  <% end %>
  <%= submit_tag l(:button_apply) %>
<% end %>