RRXS: Redundancy reducing XML storage in relations Yi Chen, Susan B. Davidson, Carmem S. Hara, and Yifeng Zheng   View Paper (PDF)   Return to XML Matching & Storage (Session A5) Abstract Current techniques for storing XML using relational technology consider the structure of an XML docu- ment but ignore its semantics as expressed by keys or functional dependencies. However, when the seman- tics of a document are considered redundancy may be reduced, node identifiers removed where value-based keys are available, and semantic constraints validated using relational primary key technology. In this paper, we propose a novel constraint defini- tion called XFDs that capture structural as well as semantic information. We present a set of rewriting rules for XFDs, and use them to design a polynomial time algorithm which, given an input set of XFDs, computes a reduced set of XFDs. Based on this al- gorithm, we present a redundancy removing storage mapping from XML to relations called RRXS. The effectiveness of the mapping is demonstrated by ex- periments on three data sets. ©2004 Association for Computing Machinery