CODEWITHSUNDEEP
ruby-on-railsruby
Dave Olson
Dave Olson

Reputation: 252

How do I access data from a joined table in my index.html.erb?

I have a Rails 4 app with two models Campus and Stat. Campus has_many stats and Stat belongs_to Campus.

The problem I have is I can the data from my Campus table in my show action, but not in my index action. Here's the relevant code from the controllers.

  def index
    @stats = Stat.all
  end

  def show
  end

Here's my show.html.erb:

<p id="notice"><%= notice %></p>
<p>
  <strong>Attendance:</strong>
  <%= @stat.attendance %>
</p>
<p>
  <strong>Salvations:</strong>
  <%= @stat.salvations %>
</p>
<p>
  <strong>Visitors:</strong>
  <%= @stat.visitors %>
</p>
<p>
  <strong>Offering:</strong>
  <%= @stat.offering %>
</p>
<p>
  <strong>Campus:</strong>
  <%= @stat.campus.name %>
</p>
<p>
  <strong>Date:</strong>
  <%= @stat.date %>
</p>
<%= link_to 'Edit', edit_stat_path(@stat) %> |
<%= link_to 'Back', stats_path %>

It's outputs the following:

Attendance: 23

Salvations: 0

Visitors: 3

Offering: 5000.0

Campus: Revelstoke

Date: 2013-07-05

Edit | Back

Here's the relevant portion of my index.html.erb:

<% @stats.each do |stat| %>
  <tr>
    <td><%= stat.attendance %></td>
    <td><%= stat.salvations %></td>
    <td><%= stat.visitors %></td>
    <td><%= stat.offering %></td>
    <td><%= stat.date %></td>
    <td><%= stat.time %></td>
    <td><%= stat.campus.name %></td>
    <td><%= link_to 'Show', stat %></td>
    <td><%= link_to 'Edit', edit_stat_path(stat) %></td>
    <td><%= link_to 'Destroy', stat, method: :delete, data: { confirm: 'Are you sure?' } %></td>
  </tr>
<% end %>

The output gives me a undefined method `name' for nil:NilClass for the stat.campus.name

I can't figure out why the difference. What am I doing wrong?

Upvotes: 1

Views: 444

Answers (2)

sites
sites

Reputation: 21805

First, you are not initialising @stat in show action, you could do this with:

@stat = Stat.find(params[:id])

Second, you have to be sure @stat has campus associated with it. But as you are not having problems with index, it seems your stat has campus associated, it means that status has a column campus_id which value is a valid id of table campuses.

Update

After reading your comment your stat has not a campus associated, you can show an empty string in these cases with:

  <td><%= stat.campus.try(:name) %></td>

Upvotes: 0

nicosantangelo
nicosantangelo

Reputation: 13726

It looks like you have a stat with no campus associated to it in your database.

To check witch one is it, you could go to the rails console and check the campus_id property, printing Stat.all,

That can happen if you are adding your stats programmatically, or maybe you added a form without every model property.

If you don't want that to happen you can use validates in your model. Check this link.

Upvotes: 1

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