Bidirectional transformation between relational data and XML document with semantic preservation and incremental maintenance

Abstract

XML has become the standard for interchanging data between web applications because of its modeling flexibility. Meanwhile, relational databases are currently by far the most commonly used type of databases, and can be found in most organizations. As a result, there are good reasons for using both XML and database technologies together. Relational databases provide strong management and security features while XML, being plain text, can easily be sent across a network using different platforms. With relational databases as a standard data storage format, and with XML as a standard data exchange mechanism, we have an ideal partnership to store and serve data for creating loosely coupled, networked applications. In recent years, a considerable amount of research has been done on translating relational data into XML documents and vice versa. However, one of the biggest problems is that most of the similar work focused only on the structure aspects and largely neglected the semantic constraints and correctness in the translation. Invalid transformations produce incomplete and inconsistent pictures that cause damage to organizations. We purpose a semantic knowledge preservation methodology such that data semantic constraints are preserved during transformation to ensure a correct relational schema. The proposed methodology, XTOPO (XML Topology) is a general, dynamic and efficient tool for publishing relational data as XML documents and storing XML back into relational format. Relational data is translated into XML structure according to the relational data semantic. An XML document is decomposed into tables on the basis of its tree structure and stored in a relational database. Also, we propose two ways for storage of an XML document: with schema and without schema. An application of XTOPO is to replicate an XML database. A relational database and its replicate counterpart XML database can be processed in parallel for both internal data processing computing and external data transmission on the Internet. In summary, this thesis shows a mechanism for combining the translation between XML documents and relational database into a general methodology. The proposed methodology captures data semantics and dependency constraints into a knowledge-based repository. The data transformation can be performed from relational database to XML document and vice versa. The contribution of this thesis includes feasibility of converting data between relational and XML with data semantic preservation, and possible maintenance of a replicate XML database with incremental changes. The application of the methodology is B2B and B2C data exchange for the information highway on the Internet.

Date of Award	15 Jul 2005
Original language	English
Awarding Institution	City University of Hong Kong
Supervisor	Shi Piu Joseph FONG (Supervisor)