基于R－图的查询有效性判断方法

R-Graph Based Determination of Query Efficiency

在数据库的操作中查询是最基本的，本文提出了用改进的ＡＮＤ／ＯＲ图（Ｒ－图）来表示一组给定的函数依赖集和数据库中的关系模式集合的方法，并给出了一个算法，用来判断从已知的库中是否能导出用户查询所需的新模式．

In general,retrieval is an essential part of database processing.ms paperPresents a malled AND/OR graph, R-graph, in order tO display a given set of functionaldependencics and a collection of relations representing a database. ms paper alsoproposes a method which determine Whether a required relation can be derived from a givendatabase.