Ruby on Rails：如何获取和显示后代记录？

Question

I have a parent model that has many children:

class Band < ActiveRecord::Base
  has_many :concerts
end

class Concerts < ActiveRecord::Base
  belongs_to :band
end

Now I would like to display them in my index view, but I can't figure out the syntax for displaying the children records:

<% @bands.each do |band| %>
  Band name: <%= band.name %>
  Concerts:
  <ul>
    <% @bands.concerts.each do |concert| %>
      <%= concert.location %>
    <% end %>
  </ul>
<% end %>

I'm getting an error like undefined method 'concerts' for #<Array:0x00000102c537f0> . What is the proper way for fetching and displaying the descendent models?

Answer 1

You were really close, but you need to change @bands.concerts.each to band.concerts.each .

<% @bands.each do |band| %>
  Band name: <%= band.name %>
  Concerts:
  <ul>
    <% band.concerts.each do |concert| %>
      <%= concert.location %>
    <% end %>
  </ul>
<% end %>