CODEWITHSUNDEEP
ruby-on-railsrelationshipnullhas-one
rfcabal
rfcabal

Reputation: 119

ruby on rails relationship error

I have a problem with relationships in ruby on rails.

I have a 1:1 relationship between two tables Professionals and Users. So I used belongs_to and has_one.

professional.rb

class Professional < ActiveRecord::Base
  attr_accessible :id, :nid
  has_one :user 
end

user.rb

class User < ActiveRecord::Base
  require 'digest/md5'

  attr_accessible :email, :first_name, :last_name, :password, :password_confirmation, :professional_id
  before_save :encrypt_password
  belongs_to :professional
end

My problem is when I want to show one by one row, I got this error

undefined method `id' for nil:NilClass

<td><%= item.professional.id %></td>

and this is my code for index.html.erb

<h2>User Dashboard</h2>
<%= link_to "Log Out", logout_path %><br />
<%= link_to "Create a User", '/register' %>
<%= link_to_function "Back", "history.back()" %>
<hr>
Display all users' information<br />
<%= form_tag users_path, :method => 'get' do %>
  <p>
    <%= text_field_tag :search, params[:search] %>
    <%= submit_tag "Search", :first_name => nil %>
  </p>
<% end %>

<table width="0%" border="0">
  <tr>
    <th scope="col">ID</th>
    <th scope="col">Firstname</th>
    <th scope="col">Lastname</th>
    <th scope="col">Email</th>
    <th scope="col">National ID</th>
  </tr>
  <% if [email protected]? %>
  <% for item in @users %>
  <tr>
    <td><%= link_to item.id, user_path(item) %></td>
    <td><%= item.first_name %></td>
    <td><%= item.last_name %></td>
    <td><%= item.email %></td>
    <td><%= item.professional.id %></td>
  </tr>
  <% end %>
<% else %>
<% end %>
</table>

I hope you can help me guys.

Upvotes: 0

Views: 67

Answers (1)

Alireza
Alireza

Reputation: 2691

It's probably happening because no Professional record has been assigned to that particular user. To prevent the error for users that have no professional record you can do this: 

<td><%= item.professional.id if item.professional.present? %></td>

Upvotes: 1

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