存在多值依赖的XML DTD规范化研究

XML DTD文档中可能包含由非函数依赖引起的数据冗余和操作异常，首先从消除DTD文档内数据冗余的角度出发研究了文档的规范化的问题，讨论了在DTD文档中存在多值依赖的情况下，如何规范XML文档，提出了以DTD为模式的XML文档的多值依赖的概念。然后基于多值依赖的概念，提出了XML文档的一种多值依赖范式MXNF。最后在此基础上提出了把一个XML文档的DTD无损联接地分解成为符合MXNF的规范化算法，来规范存在多值依赖的XML DTD文档，并给出了该算法的分析说明。

Study of Normalization Existing MVD in XML DTD

XML DTD documents may contain data redundancies and operation anomlies due to non-functional dependencies.First the normalization problem of XML DTD is studied,which should avoid the occurrence of redundant information in documents,discusses how to narmalize XMLdocument when existing MVD in XML DTD document,The concept of multi-valued dependency for XML documents with DTDs as their schemas is proposed in this paper.Second a XML normal form,Multivalued XML Normal Form(MXNF),is defined based on the concept of multi-valued dependency.Finally,a lossless join decomposition algorithm for transforming an XML document's DTD into MXNF is also given,and to normalizing this XML DTD document.