摘要
一、引言 WWW的迅速发展,使其成为全球信息传递与共享的日益重要和最具潜力的资源,如何管理WWW上的大量信息,以满足用户不断增长的高质量的信息需求?WWW作为一种新的环境资源,为新技术的产生开辟了新的领域,同时也为传统技术(如数据库。
Now the prevalent technique of Web query is information retrieval based on keyword matching , but this way can not adapt itself to the advanced, complex, structural, and semantic querying demands raised by various Web users. At present,the Web query goes mainly in two directions:one is to perfect information retrieval technique to support structure search as well as semantically content search,the other one is to introduce database query technique into the Web context,such as declarative query language(e. g. SQL,OQL etc).a formal semantics in the form of either calculus or algebra,and exploitation of database schema etc. A new tide is basing the query over XML data,so the XML data query is another active research object.
We introduce some prototypes of Web query languages,and made a comparison between these languages. We also mentioned somistructured data query languages(e.g. Lorel,UnQL). As a paradigm of XML data query language,we presented XML-QL,and a unified approach querying both kinds of data smoothly. In the end,we analyzed both the theoretical flaw and the practical deficiency of semistructured data model and its query language.
出处
《计算机科学》
CSCD
北大核心
2001年第2期1-5,共5页
Computer Science
关键词
信息检索系统
数据库
WEB
数据查询
WWW
Semistructure, Information retrieval, Database queries,Web query, XML-QL, Unified approaches
