CPI: Constraints-preserving inlining algorithm for mapping XML DTD to relational schema

As Extensible Markup Language (XML) is emerging as the data format of the I nternet era, there are increasing needs to efficiently store and query XML data. One path to this goal is transforming XML data into relational format in order to use relational database technology. Although several transform ation algorithms exist, they are incomplete in the sense that they focus on ly on structural aspects and ignore semantic aspects. In this paper, we pre sent the semantic knowledge that needs to be captured during transformation to ensure a correct relational schema. Further, we show an algorithm that can (1) derive such semantic knowledge from a given XML Document Type Defin ition (DTD) and (2) preserve the knowledge by representing it as semantic c onstraints in relational database terms, By combining existing transformati on algorithms and our constraints-preserving algorithm, one can transform X ML DTD, to relational schema where correct semantics and behaviors are guar anteed by the preserved constraints. Experimental results are also presente d. (C) 2001 Published by Elsevier Science B.V.