数据密集(data-intensive)型Web站点是指那些将大量的异构数据源的数据进行集成以后所生成的Web站点.此类站点的建设可以划分为3项主要任务:数据的访问与集成、站点结构的构造(指定各页面所含内容以及各页之间的链接)和页面的HTML表示.以XML以及来自W3C的相关规范为基础,构建了一种Web页面定义语言WPDL(Web page definition language).给出了WPDL的一个简化的EBNF表示,并举例说明了WPDL的关键特性.并且说明,使用这种说明式的查询语言(declarative query language),可以将数据访问、站点结构生成与页面表示彼此分离开来,使站点的重构(restructuring)、重用(reusability)和完整性约束的实施(integrity constraint enforcement)成为可能.

Data-Intensive Web sites refer to the Web sites which integrate data from multiple heterogenous data sources. Building data-intensive Web sites is a data-management problem. Generally speaking, this process consists of three main programming tasks: accessing and integrating the data available in the site, building the structure of the site, i.e., specifying the data in each page and the links between pages, and generating the HTML representation of pages. In this paper, a Web page definition language named WPDL is proposed on XML techniques and related recommendations from W3C.A brief EBNF grammar rule of WPDL is given,and the key features of WPDL are described with wieh a couple of examples.It is argued that the three tasks can be separated with that kind of declarative query language.Thereby it is possible to maintain a data-intensive Web site with restructuring,reusability and integrityconstraint enforcement.