Multivalued dependencies and a 4NF for XML

Abstract

While providing syntactic flexibility, XML provides little semantic content and so the study of integrity constraints in XML plays an important role in helping to improve the semantic expressiveness of XML. Functional dependencies (FDs) and multivalued dependencies (MVDs) play a fundamental role in relational databases where they provide semantics for the data and at the same time are the foundation for database design. Since XML documents are closely coupled with relational databases in that XML documents are typically exported and imported from relational databases, the study of FDs and MVDs in XML is of fundamental significance in XML research. In this paper we define multivalued dependencies in XML (XMVDs). We then propose a normal form for XML documents in the presence of XMVDs and justify our normal form by showing that it ensures the elimination of redundancy. © Springer-Verlag Berlin Heidelberg 2003.