CODEWITHSUNDEEP
ruby-on-rails
Colm Troy
Colm Troy

Reputation: 1947

Rails - Accessing one to many variables in a table loop

I've got a simple one to many relationship between tasks and priorities.

class Task < ActiveRecord::Base
    attr_accessible :subject, :body, :priority_id, :company_id, :status_id, :user_ids
    has_and_belongs_to_many :users
    belongs_to :priority
    belongs_to :company
    belongs_to :status
end


class Priority < ActiveRecord::Base
    attr_accessible :name
    has_many :tasks
end

From my tasks/show.html.erb view

<%= @task.priority.name %>

This works.

However in my tasks/index.html.erb

<% @tasks.each do |task| %>
  <tr>
    <td><%= task.subject %></td>
    <td><%= task.body %></td>
    <td><%= task.priority.name %></td>
    <td><%= link_to 'Show', task %></td>
    <td><%= link_to 'Edit', edit_task_path(task) %></td>
    <td><%= link_to 'Destroy', task, confirm: 'Are you sure?', method: :delete %></td>
  </tr>
<% end %>

The call to task.priority.name does not work.

It throws a NoMethodError.

I'm guessing this is a really stupid newbie mistake but I can't for the life of me figure it out. It would have assumed that the Active Record magic would have filtered down into a look like this.

Upvotes: 1

Views: 314

Answers (3)

Gawyn
Gawyn

Reputation: 1156

Given that there is no validation of the presence of priority in task, it's quite possible that you are calling "name" on nil. Validate the presence of priority (with validates_presence_of) or check it exists before printing it as Christoph says.

Upvotes: 0

Christoph Petschnig
Christoph Petschnig

Reputation: 4157

I guess your NoMethodError comes on nil:NilClass. Try:

  <%= task.priority.name if task.priority %>

Upvotes: 3

Sebastien
Sebastien

Reputation: 6660

Are you sure you have well created all the models and links with primary keys in your database? I think you link to a task with a priority id (prority_id) which doesn't exists.

Check your datas.

Upvotes: 0

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