系统地描述了网上购物订单的xml格式，其中的结构清晰-Systematically describes the order of the xml format of online shopping, in which the structure is clear

xsd课后作业，根据给出的描述订单的XML文档，结合所学知识，创建一个W3C XML Schema文档，并检查XML文档的有效性。-xsd after-school jobs, according to the descr iption given in order of XML documents, combined with the knowledge to create a W3C XML Schema document, and check the validity of the XML