Secondly, we made use of views on mediated schema to describe the content of data sources. Then we novelly adopt ' answering queries using views ' technique into XML query reformulations. The mechanism can express fine-grained differences between data sources. 采用在XML的中介模式上的视图定义来描述数据源的内容,第一次在XML的集成查询中使用利用视图重写查询技术,使得模型化数据源内容间的微妙差别成为可能。