ruby on rails - no method error in one to many relationship -

models/user.rb

class user < activerecord::base  has_many :clubs, :dependent => :destroy  has_many :announcements, :dependent => :destroy end 

models/announcement.rb

class announcement < activerecord::base  belongs_to :user  belongs_to :club end 

models/club.rb

class club < activerecord::base   belongs_to :user   has_many :announcements, :dependent => :destroy end 

controllers/announcements/announcements_controller.rb

def index  @announcements = announcement.find(:all, :include => [:user, :club]) end 

problem:

when type code,

views/announcements/index.html.erb

<% @announcements.each |announcement| %>  <%= announcement.user.username %> <% end %> 

i error:

nomethoderror in announcements#index  undefined method `username' nil:nilclass 

when change code this, works.

<% @announcements.each |announcement| %>  <%= announcement.club.user.username %> <% end %> 

why first code not working? difference between these codes. thanks.

it looks you've got announcement has no user set, have club in turn have user. perhaps consider adding validation require :user_id column on announcement present.