Translating XQuery to SQL based on Query Forests

Abstract

It is a difficult task to transform an XQuery posed gainst an XML view into an SQL appropriate for the original relational schema to get data. The main reason lies in the difference of the schema modeling power and the query syntax. In this paper, we propose to represent an XQuery as a set of for trees and return trees, or called the query forests as a whole, based on the functionality of the path expressions specified in each clause. These trees show the structural constraint of the input query and serve as the vehicle to combine the mapping SQL fragments into a complete SQL statement. A prototype has been implemented to show the effectiveness of the transformation process.