Question

This helped for display on an individual ‘items’ show page
Accessing an attribute of a linked model in Rails

However I’m having trouble doing the same for an ‘all items table’

...
<% @items.each do |item| %>
...
<td><%= item.room.name %></td>
...

Clearly where one room has many items.

only this works:

<td><%= item.room_id %></td>

I can’t seem to use it there, gives:

undefined method `name' for nil:NilClass

Answer 1

Have a look at Rails’ Delegate module:

class Item < ActiveRecord::Base
  # ...
  delegate :name, :to => :room, :allow_nil => true, :prefix => :room
end

This will add the instance method room_name to Item, which will fail more gracefully (returning nil if there is no room, instead of the NilClass error).