Ruby on Rails：将不同控制器的动作包含到另一个控制器的索引视图中

Question

I am currently into learning Ruby on Rails and I am stuck with a pretty simple thing. I already tried to google it (or look it up here), but I could not find the right answer (due to my RoR-beginnings it might searched with the wrong terms).

I am working on a small learning project to list different items (items_controller). Each of these items belong to a category. But because I want the users to either create, update or delete a category I created a categories_controller. Both controllers and views are working fine, but I want to include the Category of each item on the index-view (which is also the root_path) of my Items Controller. Here I get stuck (with the code and the logic behind it as well). What is the best way to do this?

Somehow I managed to get the category name into the edit.html.erb-form of the items_controller, but I don't really understand how:

items_controller:

def edit
  @item = Item.find(params[:id])
  @categories = Category.all.map{ |c| [c.name, c.id] }
end

edit.html.erb (this is actually in _form.html.erb and rendered in edit.html.erb):

<%= simple_form_for @item, :html => { :multipart => true } do |f| %>
  <%= f.select :category, @categories %>
  <%= f.input :title %>
  <%= f.input :url %>
  <%= f.button :submit %>
<% end %>

Answer 1

If you want to include the category of each items, You need to specify which column of categories table you want to display. Example : a column called name :

<% @items.each do |item| %>
 <%= item.category.name %>
<% end %>