Question

I’m creating a Rails application, and I’ve hit a bit of a snag. I want a ‘create new record for DataType1’ form that not only creates a new row for DataType1, but also inserts up to four new rows for DataType2.

I know all about fields_for, but my problem is that I need to submit up to four DataType2s, and the only connection they have to DataType1 is that they are referenced via a field in DataType2.

Here’s the simplified database:

create_table :data_type_1 do |t|   t.string     :title   t.text       :body    t.timestamps end  create_table :data_type_2 do |t|   t.belongs_to :parent    t.timestamps end 

Now, I have the relationships all set up and everything; that’s not the problem. The problem is that I just can’t seem to figure out how to pass the params for the DataType2s in with the params for the new DataType1. Once someone shows me how I should go about doing this, I can set up the new DataType2s to associate with the new DataType1 fairly easily.

Here’s what I have for the form at the moment:

<% form_for(@data_type_1) do |f| %>   <%= f.error_messages %>    <p>     <%= f.label :title %><br />     <%= f.text_field :title %>   </p>    # Etc...    <p>     # New items need to be iterated here     # DataType2[1]: [         ]     # DataType2[2]: [         ]     # DataType2[3]: [         ]     # DataType2[4]: [         ]     # (Note that these numbers are just examples.)   </p>    <p>     <%= f.submit 'Create' %>   </p> <% end %> 

I’m relatively new to Rails, and I apologize if this question rambles a bit.

Answer 1

This RailsCast talks about inserting lists of ‘DataType2’ into ‘DataType1’. The interesting parts are these

app/views/projects/_form.html.erb

  <% for task in @project.tasks %>     <% fields_for 'project[task_attributes][]', task do |task_form| %>       <p>         Task: <%= task_form.text_field :name %>       </p>     <% end %>   <% end %> 

app/models/project.rb

def task_attributes=(task_attributes)   task_attributes.each do |attributes|     tasks.build(attributes)   end end