Question

I have two models:

class Product < ActiveRecord::Base
  attr_accessible :amount, :name, :unit, :description, :stock, :limit
  has_many :cart_rows
  has_one :inquery
end

and

class Inquery < ActiveRecord::Base
  attr_accessible :product, :text, :phone, :zip, :product_id, :state, :street, :city
  belongs_to :product
end

In my index of Inqueries view I have:

<% @inqueries.each do |inquery| %>
  <%= inquery.product.name %>
  <%= inquery.text %>
<% end %>

And I get the following error: undefined method 'name' for nil:NilClass

What am I doing wrong? Does has_one behave differently than has_many?

Answer 1

I built an app based on the info you described here, and was able to reproduce your problem by having an Inquery record with nil values for product (also for text). You may wish to add better validators so that Inqueries with nils cannot be saved.

Here’s a paste from my rails console session:

  Inquery Load (0.1ms)  SELECT "inqueries".* FROM "inqueries" 
#<Inquery:0x00000002c03e40>
 => [#<Inquery id: 1, text: nil, phone: nil, zip: nil, product_id: nil, state: nil, street: nil, city: nil, created_at: "2012-08-17 15:23:49", updated_at: "2012-08-17 15:23:49">] 

1.9.3p194 :002 > Inquery.all.each { |n| puts n.product.name }
  Inquery Load (0.2ms)  SELECT "inqueries".* FROM "inqueries" 
NoMethodError: undefined method `name' for nil:NilClass

As an aside, and now for some unsolicited advice: a field with the same name as a keyword, “text”, is a really bad idea. You might not shoot yourself in the foot today, but you will at some point. Consider renaming the text field to usertext or description or something like that.