Designing And Implementation Of An Extensible XQuery-SQL Translation Model

As a markup language, XML is now a proposed standard for web information publishing, data storing and information exchanging. More and more application areas are producing XML documents on the web. It is critical to have efficient mechanisms to store XML documents to exploit the full power of the new technology. Mature relational database is widely used to store XML documents. However, this brings two problems: how to transfer XML documents from XML to relational database; how to convert XML queries to relational queries. This paper mainly studies the second problem.This paper studies a number of translation strategies, and finds out that there's no existing technologes to our best knowledge can solve this problem soundly. Morever, query translation relies on mapping strategy. In order to support new mapping strategy, new query processor should be built. So it is helpful to design and implement a query translation system, which enables users to extend it to support new mapping strategy at a low cost.Based on the idea above, this paper designed and implemented an Extensible XQuery-SQL Translation Model (EXSM), which supports the XQuery-SQL translation and enables user to extend it at a low cost to support new mapping strategy.In order to enable users to extend EXSM at a low cost, EXSM is divided into the schema mapping component and the query translation component. The first component processes schema mapping, and defines a series of API, which enables user to exntend EXSM more conveniently and be unconscious of the top component's implementation. Query translation component is used to translate XQuery to SQL. It is well designed so that it only depends on the abstract API of the schema mapping component, and would not be affected by the changes of mapping strategy. Morever, EXSM provides a complete XQuery-SQL translation solution, including the schema mapping based on Schema and the translation from original XQuery statement to the destination SQL statement. EXSM have powerful function and is easy to be extended, which makes up the characteristic and originality of this paper.Finally, we give a conclusion of the advantages as well as drawbacks of our approach, which will guide our research work in the future.