XML函数依赖研究综述

A survey on XML functional dependencies

函数依赖作为数据库规范化的基础在关系理论中起着重要的作用。近年来,XML得到广泛应用并已成为互联网上数据传输和交换的标准。由于XML半结构化的特性,使得如何定义XML函数依赖使其具有更强的描述能力,以及如何解决相应的逻辑蕴涵问题成为当今学术界所面临的挑战。针对这些问题,系统地描述了目前关于XML函数依赖的研究现状,特别是把分析的重点放在如何定义函数依赖、判断其蕴涵关系以及从XML文档中发现函数依赖等问题上。最后讨论了诸如类型化函数依赖关系等一些相关的研究方向。

The concept of functional dependencies plays an important role in database theory since it is the basis of normal forms that are used to produce well-design schema.Due to the complexity of the semi-structured XML model,it is a challenge to define the functional dependencies and study the nature of those dependencies such as their capability of representation,logical implication and corresponding normal forms.The previous works in this area are surveyed and the approaches they deployed are described.Particularly,the paper focus on the comparison of functional dependencies definitions,the problem of logical implication and the discovery of dependencies.At last,some novel problems referring to dependencies such as relationship between value and type in shortly are discussed.