XML强闭包依赖范式的研究  

Improving the normal form of the strong inclusion dependency in XML

作　　者：殷丽凤[1] 郝忠孝[1,2] 

机构地区：[1]哈尔滨理工大学计算机科学与技术学院,黑龙江哈尔滨150080 [2]哈尔滨工业大学计算机科学与技术学院,黑龙江哈尔滨150001

出　　处：《哈尔滨工程大学学报》2010年第4期496-502,共7页Journal of Harbin Engineering University

基　　金：黑龙江省自然科学基金资助项目(F200702)

摘　　要：为了解决从数据库整体的角度来消除基于不完全信息的XML数据冗余问题,研究了在不完全信息环境下XML数据库的各个模式之间存在的XML强闭包依赖引起数据冗余的判定条件和规范化算法.首先,给出了XML强函数依赖和XML强闭包依赖两者互不影响的定义;其次,提出了XML强函数依赖和非循环XML强闭包依赖互不影响的判定定理,研究了XML强闭包依赖范式以及相应的判定定理;最后,提出了把XML数据库模式转化为XML强闭包依赖范式的规范化算法,对时间复杂度进行了分析.该算法消除了冗余路径,避免了更新异常,实现了整个XML数据库模式更合理的设计.XML fosters data redundancy and on a global scale could lead to massive accumulations.Conditions were studied for judging and reducing data redundancies arising from XML＇s strong inclusion dependency among XML database schemas.First,non interaction between XML＇s strong functional dependency and XML＇s strong inclusion dependency was defined.Second,a theorem determining non interaction between XML＇s strong functional dependency and noncircular XML＇s strong inclusion dependency was presented.The normal form of XML＇s strong inclusion dependency and the corresponding determinant theorem were then studied.Finally,the logic of normalization was formalized and time complications analyzed.This removed the redundancies of paths,eliminated update anomalies and achieved a more reasonable design for global XML database schemas.

关 键 词：不完全信息 XML强函数依赖 XML强闭包依赖 XML强闭包依赖范式 

分 类 号：TP311.13[自动化与计算机技术—计算机软件与理论]