name type

• If you plan to reuse a data type within your schema , create a named type and refer to it in all the elements that require that data type
  如果计划在架构内重用某数据类型，请创建命名类型，并在需要该数据类型的所有元素中引用它。
• In china there are only two types of metro vehicles , named type a and b , but vehicle structure and technology are very different from each other for different cities
  摘要地铁车辆虽然分为a型和b型两大类，但各城市地铁车辆的技术与结构型式仍存在较大差异。