Now you can add the extra attributes for the two new sub-classes.

现在，您可以为这两个新的子类添加额外属性了。

youdao

In addition to the predefined fields, you can add extra custom fields to the extension mappings by defining custom attributes on the mappings.

除了预定义的字段外，通过对映射定义定制属性，您还可以向扩展映射添加额外的定制字段。

youdao

This should be considered an extra performance bonus rather than an incentive to convert attributes to elements, especially when data modeling considerations actually call for elements.

这应该看作是额外的性能收益，而不是将属性转换成元素的决定因素，尤其是当数据建模确实倾向于使用元素的时候更是如此。

youdao