# File lib/active_record/associations.rb, line 1378
            def column_names_with_alias
              unless @column_names_with_alias
                @column_names_with_alias = []
                ([primary_key] + (column_names - [primary_key])).each_with_index do |column_name, i|
                  @column_names_with_alias << [column_name, "#{ aliased_prefix }_r#{ i }"]
                end
              end
              return @column_names_with_alias
            end