Conversion Of Heterogeneous Xml-based Relational Database Technology Research

During the process of enterprise informationization, relational database systems are widely used and are playing some significant roles in the data management of enterprises with their mature technology, powerful data management, the reliable and stable concurrent control. But as the development of enterprise informationization, extension of application, and promotion of resources including software and hardware, the heterogeneous problems of relational database systems emerge more and more seriously. In order to exploit and apply the existed information resource more effectively, heterogenous relational database often has to be translated and moved. The merits and characteristics of XML such as platform-independent, easy to be expanded, interactive, strong semantic expression ability, and able to be formatted -make it easy to describe relational schema and serve as an intermediary in the conversion among heterogenous databases.Supported by National 863/CIMS High Tech Program-Semantic Integration of Enterprise Heterogenous Data Source, this paper takes XML as a public model and studied the conversion technology among heterogeneous relational database systems by means of bidirectional reversible conversion between relational and XML. Entity integrity constraints, referential integrity constraints, and user-defined most intergrity constraints of relational database were all preserved after the conversion.This paper puts forward two methods to translate relational schema to XML schema, and some key algorithms are designed, including reverse resolving algorithm for relational schema, key-based nesting algorithm and flatting algorithms, model-driven mapping algorithm from relational schema to XML schema. In order to solve the question that XML document was too big, the intermediate result was divided into sub-schema to realize the conversion of XML schema to relational schema. Finally, two application components to the conversion between relational schema and XML schema are builded, and an uniformed tool for conversion among heterogeneous relational database systems is developped.This tool can implement the conversion among different kinds of heterogenous database resources in a database-indenpdent and automatic manner. The algorithms for conversion between relational schema and XML schema make enterprise easily to publish its product data information on Internet/Intranet, and provide a powerful technical support for advanced integration among enterprise heterogenous data sources.