Abstract: DTD does not support the definition of the complex elements. Based on the formal definition of XML schema, the complex elements and the functional dependence were defined in XML. A new mapping method based on pivot node was proposed; it obtained the relation tables according to the pivot node and the XML functional dependences. The constraints that were represented by the XML functional dependences, as well as the content and the structure, were preserved at the same time. Much storage redundancy can be reduced. Furthermore, the relations mapped from XML were proved in Third Normal Form (3NF)．

Key words: pivot node

摘要： DTD模式不支持复杂元素类型定义，在引入Schema形式化定义的基础上，给出XML上的复杂元素和函数依赖的定义，提出一种基于轴节点的映射算法。该算法根据轴节点和XML函数依赖生成关系表，能保持XML文档的内容和结构信息,保持函数依赖，减少存储冗余,并且证明映射后的关系模式满足3NF。

关键词: 关系模式, 函数依赖, 轴节点, relation mode, functional dependency