- 作者: Jorng-Tzong HORNG, Yung-Yuh TAI
- 中文摘要: The World Wide Web (WWW), a hypertext based, distributed collection of documents connected by hypertext links, contains millions of documents, thereby necessitating the ability to control navigation. This study, presents a query language to restrict navigation on the WWW. Query-based access mechanisms represent a fundamental solution to navigation problem in hypertext applications. Queries with structural search capabilities allow users to retrieve collections of information from a hypertext network based on a specification of their structures. In this paper, we propose a pattern-based structural query language for the WWW. This study also defines a set of patterns and uses pattern expressions to specify structural conditions in a query. The proposed pattern-based structural query language integrates the pattern-based query formulation and select-from-where construct of the structural query language (SQL). In addition, schema mapping rules are proposed to map the nodes and links of a hypertext application into objects and associations of an object-oriented database. Objects and their associations in an object-oriented database are uniformly represented by association patterns. A pattern-based structural query in hypertext systems is then translated into A-algebra expressions for query processing.
- 英文摘要: --
- 中文關鍵字: hypertext systems, structural query, object-oriented database, query processing, association algebra
- 英文關鍵字: --