rails: how to update multiple records using "accepts_nested_attributes"

Question

Let's say I have a cat model and a life model. And let's say a cat (@cat) has_many lives, and a cat accepts_nested_attributes for a life. Now, if I wanted to update 7 lives (@lives) at once, using one form_for(@cat), how would that form look like? This is what I've tried, but in this form only the attributes for the last life are passed to the params hash:

  <%= form_for(@cat) do |f| %>
    <% @lives.each do |life| %>
      <%= f.fields_for(life) do |l| %>
        <%= l.input :date_of_birth, as: :date %>
      <% end %>
    <% end %>
    <%= f.submit %>
  <% end %>

Answer 1

You need to build the attributes in your controller

@cat = Cat.find(<criteria>)
@cat.lives.build

In your example, you have a loop inside a loop. Try this:

<%= form_for(@cat) do |f| %>
  <%= f.fields_for(:lives) do |l| %>
    <%= l.input :date_of_birth, as: :date %>
  <% end %>
  <%= f.submit %>
<% end %>