摘要： 数据依赖在数据库设计中起着十分重要的作用。自Codd提出函数依赖,Fagin引入多值依赖后,近年来人们又根据设计中的需要引入了许多种新的依赖。然而对这些依赖可从原则上控是否具备完备的公理系统划分为两大类,因为完备公理系统往往是具有有效判定算法为先决条件。本文给出了一种具有完备公理系统的充要条件,并利用它来证明几种依赖(嵌入型多值依赖、嵌入型联接依赖、包含依赖与函数依赖)不具备完备的公理系统。

Abstract: Data dependencies play a very important role in the database design. Since functional dependency and multivalued dependency were put forward by E. F. codd and R. Fagin respectively many other kinds of dependencies have been introduced by database designers according to the requirements in their designs. These dependencies can be divided into two large categories depending on whether there is a finite complete axiomatization for the dependencies, because the finite cemplete axiomatiza-tion is generally a prerequisite for efficient decision algorithms. In this paper, a suffi cient and necessary condition for finite complete axiomatization to exist is given. Based on condition, the paper proves several kinds of dependencies (EMVD, EJD and FD interaction with IND) have no finite complete axiomatization.