define_read_method

# File activerecord/lib/active_record/attribute_methods.rb, line 146
        def define_read_method(symbol, attr_name, column)
          cast_code = column.type_cast_code('v') if column
          access_code = cast_code ? "(v=@attributes['#{attr_name}']) && #{cast_code}" : "@attributes['#{attr_name}']"

          unless attr_name.to_s == self.primary_key.to_s
            access_code = access_code.insert(0, "missing_attribute('#{attr_name}', caller) unless @attributes.has_key?('#{attr_name}'); ")
          end
          
          if cache_attribute?(attr_name)
            access_code = "@attributes_cache['#{attr_name}'] ||= (#{access_code})"
          end
          evaluate_attribute_method attr_name, "def #{symbol}; #{access_code}; end"
        end