【作者】 凌波； 吴永辉；

【Author】 Ling Bo~(1,2,3) and Wu Yonghui~(1,3) 1(Laboratory of Computer Science,Chinese Academy of Sciences,Beijing 100080) 2(Pudong Executive Leadership Academy of China,Shanghai 201204) 3(Department of Computer Science and Engineering,Fudan University,Shanghai 200433)

【机构】 中国科学院计算机科学重点实验室； 中国浦东干部学院； 复旦大学计算机科学与工程系；

【摘要】 XML数据库模式规范化设计是产生一组相关联的、能很好地表示数据间依赖关系、而且消除了冗余的XML模式或DTD,以更好地进行信息检索.XML数据库模式中某些数据依赖是冗余存在的原因.因此在XML数据库模式中数据依赖与冗余的性质以及关联是其规范化设计要解决的关键问题.XML数据库模式的数据依赖包括属性间数据依赖和元素间的数据依赖.在以往的工作中,已经给出XML数据库模式中元素间的数据依赖及其所关联的显式冗余的有关性质,并基于此实现和验证相应的XML数据库模式规范化设计算法.分析XML数据库模式中属性间的数据依赖、元素间的数据依赖及其关联,定义XML数据库模式数据依赖及其相关联的隐式冗余,并论证XML数据库模式中隐式冗余不存在的充分条件.更多还原

【Abstract】 Normalization design of XML database schemes is generating a set of related XML schemas or DTDs that represent data dependencies and eliminate redundancies.The reason why redundancies exist in XML database schema is that there are some data dependencies in it.So properties and relationships for data dependencies and redundancies in XML database schema are key problems that should be solved for its normalization design.Data dependencies in XML database schemes consist of data dependencies among attributes and among elements.In previous efforts,properties for data dependencies among elements and related explicit redundancies were given,and based on it corresponding normalization design algorithms for XML database were implemented and proved.In this paper,data dependencies among attributes and among elements in XML database schema and their relationships are analyzed,data dependencies and implicit redundancies in XML database schema are defined and the necessary condition that implicit redundancies don’t exist in XML schemas is proved.更多还原