XML Schema 提供了两个在实例文档中使用的特殊属性，用于指出模式文档的位置。这两个

属性是：xsi:schemaLocation 和xsi:noNamespaceSchemaLocation，前者用于声明了目标名称

空间的模式文档，后者用于没有目标名称空间的模式文档，它们通常在实例文档中使用。-XML Schema provides two in the instance document using the special attribute is used to indicate the location of schema documents. These two properties are: xsi: schemaLocation and xsi: noNamespaceSchemaLocation, the former is used to declare a target namespace of the schema document, which is no target namespace for schema documents, they are usually in the instance document.