支持抽象数据类型的关系数据库系统的设计

DESIGN OF A RELATIONAL DATA BASE SYSTEM SUPPORTING ABSTRACT DATA TYPES

抽象数据类型(ADT_s)是一个数据结构及其相关操作集的封装。本文把关系模型加以扩充,使其可将域任意地定义为抽象数据类型;在这些类型上可以定义原语操作,还可以定义聚集函数操作。本文还提出了将dbaseⅢ扩充为可支持ADT_s的设计思想,并给出了框图。文中提出的方法强调相关信息的局部性,可使得定义的新类型与原有DBMS的交互尽量少。

An Abstract Data Type (ADT) is an encapsulation of a data structure with its relative operation set. In this paper we extend the relational model so as to define ADTR as new data types for domains. If necessary, we can define primitive operations as well as aggregate functional operations on the new data types. The idees of extending dBASE III to support ADTp and the frameworks are also proposed. A methodology focusing on the localization of related information minimizes interaction between the new data types and the original DBMS.