关系模式分解和设计的泛系研究及关系闭包的微机实现

Pansystem Research of The Decomposition and Designof Relational Schema and MicroComputerRealization of Relational Closure

从泛系方法论的观点出发，对关系数据库理论的基本问题从新的角度进行了概括和分析，提出了一些有待深入探讨的问题．通过一个实例，说明了在关系模式的分解中是否蕴含了没有包括在内但可供选择和分析的子模式，以及这些子模式如何确定并求出．最后得到了一个判定定理．在这些分析讨论后，对关系理论中的核心问题之一——求属性子集的闭包，在与ＩＢＭＰＣ兼容微机上，使用高级语言Ｐａｓ－ｃａｌ进行了程序设计．通过对一个实例进行运行，证明其效果很好．

This paper summarizes the basic problems in relational database theory from the viewpoints of pansystem methodology. Some suggestions required to go further discussing are advanced. With an example, the author illustrates that if a subschema available is logically implied in a certain partition of a relational schema and how to find it out. Moreover a decisive theorem is obtained. Then the author develops a programm using PASCAL language for one of the key problems——how to find out the closure of an attribute subset subject to a functional dependency set on a given relational schema. The result is proved to be satisfactory for an example on an IBM PC compitable computer.