摘要
从XML数据安全性考虑,在已经使用XQuery作为查询语言的前提下,为增强XQuery对XML文档查询能力,创造了类似关系数据库视图的XQuery视图机制,使得不同用户对XML文档具有不同的查看能力,保证查询安全可靠。XQuery视图由查询来定义其内容,分为实视图和虚视图两种。虚视图根据需要计算视图定义的查询,而实视图不管以后是否需要,只要一创建就计算其视图定义,类似关系数据库视图,实视图和虚视图对于数据查询都是必要的。
Use XQuery as a querying language. Considering the safety of XML data, create XQuery view to build up XQuery's querying ability on XML. Thus users can use XML data from different view. It is very like view of relational databases and can guarantee the safety and reliability of querying processing. XQuery view is defined by XQuery strings. It has two formats: materialized view and virtual view. Virtual view does query when necessary, while materialized view does it when created. They are the same important to data query as the related databases.
出处
《微机发展》
2004年第12期111-113,116,共4页
Microcomputer Development
