Rails - Displaying Foreign Key References in a form - ruby-on-rails

Question

I'm doing a simple exercise with two models. Sport and Teams, defined as
rails g scaffold sport name:integer
rails g scaffold team name:integer fans:integer sport:references
(Note: The reason I'm using scaffold is rapidly prototyping so I can learn/experiment with the parts I'm not familiar with yet)
Problem is that my "sport" (i.e. the foreign key reference) is showing like the following
So it's got that weird #<blahl blah> notation to it...
<%= form_for(#team) do |f| %>
<% if #team.errors.any? %>
<div id="error_explanation">
<h2><%= pluralize(#team.errors.count, "error") %> prohibited this team from being saved:</h2>
<ul>
<% #team.errors.full_messages.each do |msg| %>
<li><%= msg %></li>
<% end %>
</ul>
</div>
<% end %>
<div class="field">
<%= f.label :name %><br />
<%= f.text_field :name %>
</div>
<div class="field">
<%= f.label :fans %><br />
<%= f.number_field :fans %>
</div>
<div class="field">
<%= f.label :sport %><br />
<%= f.text_field :sport %>
</div>
<div class="actions">
<%= f.submit %>
</div>
<% end %>
I've tried changing the one line to #team.sport.name but it results in an error undefined method 'Ice Hockey' for #<Team:0x3e7e040>... Any ideas how to properly display name from here??

Answer 1

You are using a text_field for referencing an existing object, a select with Sports as options would be more appropriate here.
This is where it has to be changed:
<div class="field">
<%= f.label :sport %><br />
<%= f.text_field :sport %>
</div>
To:
<div class="field">
<%= f.label :sport %><br />
<%= f.select :sport_id, options_for_select(Sport.all.map{|s|[s.name, s.id]}) %>
</div>
The f.select will generate a select box in HTML, the options will me all the sports in your DB.
Some documentation about it:
http://apidock.com/rails/ActionView/Helpers/FormOptionsHelper/select
http://guides.rubyonrails.org/form_helpers.html#select-boxes-for-dealing-with-models
A cleaner way would be to set a variable #sports in your controller and call it then in your views:
# in controller
def edit
#sports = Sport.scoped
#...
# in edit view
<div class="field">
<%= f.label :sport %><br />
<%= f.select :sport_id, options_for_select(#sports.map{ |s| [s.name, s.id] }) %>
</div>
Additionnal information: If you want to "pre-select" an option for the select, you have to pass it as the second argument of the options_for_select helper:
options_for_select(#sports.map{ |s| [s.name, s.id] }, params[:sport_id])
# this will select by default the option that matches the value of params[:sport_id]