Key Techniques Of Data Exchange Based On Relational Databases

With the development of e-Government, every department has accumulated large amount of heterogeneous data which are mostly stored in different relational databases. Sharing of these data is a problem often encountered in the information construction of government. XML has emerged as the de facto standard for data exchange on the web, which provides a truly open, well-defined and neutral data format to solve the sharing and exchange of data between heterogeneous databases. At the same time, data exchange between isomorphic databases under distributed environment is another urgent problem, which can be solved through the technology of synchronized update of data.With the background of e-Government development, this paper discusses the data exchange based upon XML. Firstly, it studies the integration of RDB and XML, and presents schema conversion and matching algorithms between relational model and XML. Then it discusses the technology of XML document transmission, in which some transmission methods and encryption means are analyzed and compared. On the above discussion, this paper addresses a XML-based Heterogeneous Data Exchange Layered Model (XHDELM) which has characteristic of flexibility, generality, extensibility, open, easy-realization and covers the whole course of data exchange from data extraction, transformation, mapping to communication.This paper also discusses synchronized update of data, in which conflict resolution and synchronized update under distributed environment are studied, and an incremental synchronized update policy based on transaction described with XML is proposed.Based on the above research, a XML-based data exchange system under the XHDELM frame and a database replication configure tool are implemented. Both of them have been successfully applied to the e-Government system for a certain department.