用集合映射构造NF^2中的新依赖

Constructing New Dependencies in NF^(2) by Using Set Mapping

1.引言 NF^2的一个公开问题是如何表示关系.我们认为数据依赖是一种很好的表示方法由依赖表示的数据库模式具有最小数据冗余、上佳分解。

In this paper,we study NF2 relations by applying set-mapping instead of data-correspond-ing. We consider set-mapping be a fundamental concept as a way of data dependency construction in representing NF2 relations. A series of mappings is given to build a complete mapping frame-work. Several mappings are reconstruted as data dependencies under simple conditions. Set-map-pings and their simplifications are shown by M-graph.