Drop down boxes from table data

Hi

I have another question for how best to do this. Now I have been
following the tutorial at:
http://www.tunaslut.com/learning-ruby-drop-down-lists-in-one-to-many-relationships,
however when I change the view over from

<% @cities.each do |city| %>
  <tr>
    <td><%=h city.city_name %></td>
    <td><%=h city.country_id %></td>

to:

<% @cities.each do |city| %>
  <tr>
    <td><%=h city.city_name %></td>
    <td><%=h city.country.country_name %></td>

The system breaks with the following error

NoMethodError in Cities#index

Showing app/views/cities/index.html.erb where line #12 raised:

undefined method `country_name' for nil:NilClass
Extracted source (around line #12):

when attempting to display data on cities

My questions are:

1. Is there an easier way of doing drop down boxed populated from a
table?
2. is this foreign key assignment working?
3. is this a good way of doing FK asignments? is there a better way.

Please forgive me, I'm old school, more used to the SQL statements....

Thanks again.

disruptive tech wrote:

Hi

I have another question for how best to do this. Now I have been
following the tutorial at:
http://www.tunaslut.com/learning-ruby-drop-down-lists-in-one-to-many-relationships,
however when I change the view over from

<% @cities.each do |city| %>
  <tr>
    <td><%=h city.city_name %></td>
    <td><%=h city.country_id %></td>

to:

<% @cities.each do |city| %>
  <tr>
    <td><%=h city.city_name %></td>
    <td><%=h city.country.country_name %></td>

The system breaks with the following error

NoMethodError in Cities#index

Showing app/views/cities/index.html.erb where line #12 raised:

undefined method `country_name' for nil:NilClass

...which means that city.country is nil. You have to make it not be.

Extracted source (around line #12):

when attempting to display data on cities

My questions are:

1. Is there an easier way of doing drop down boxed populated from a
table?

collection_select

2. is this foreign key assignment working?
3. is this a good way of doing FK asignments? is there a better way.

I don't see any assignment in your code.

Please forgive me, I'm old school, more used to the SQL statements....

What's that got to do with anything?

Thanks again.

Best,