Data Transformation Between XML And RDB With Constraints

With the rapid development of Internet, quick inflation of the amount or" information has taken place and there has an increasing need for efficiently managing and exchanging data , so the mature relational database technology would be in face of many new problems and challenge. It puts forward an important problem that the database technique must face how to efficiently store and manage dataon the web and how a substantial amount of conventional relational data to be converted or published as XML data. This research is a deserving topic. As Extensible Markup Language (XML) is emerging as the data format in the Internet era , XML becomes a standard for data representation and exchange on the Web, because of its high-flexibility and extensibility. Nowadays, the method to transform XML data into relational format (and vice versa) using the mature relational database technology will be an ideal way of dealing with facility and platform independence will remain. At the same time, convenient management, small-capacity storage, quick retrieval, efficient modification and high security in data management of RDB are all to retain.The key factor to the transformation of XML document and relational data is how to vividly build up the structure mapping between them. In this paper, we analyze the present algorithms and models on transformation of XML document and other format data, and study further on XML database constraint. XML functional dependency is presented based on path expression and tree model, and a sound complete set of inference rules of XML functional dependency is given. This paper also presents an approach based on DTD Element-Tree and a mapping algorithm between DTD Element-Tress and RDB. It exploits a mapping algorithm about XML documents to relations in the presence of XML functional dependencies, The structure mapping between the XML document and the RDB is built, which is used to complete the data transformation. Therefore it has important theoretic significance and practical value to the research on XML database schema normalization.