Multivalued Dependencies and a 4NF for XML

In this paper we make three main contributions. We firstly define multivalued dependencies in XML (XMVDs) and show that they generalize the definition of a functional dependency in XML (XFD) proposed in some of our earlier work. Secondly, we justify our definition of an XMVD by showing that for a very general class of mappings from relations to XML documents, a unary MVD is satisfied in a relation if and only if the corresponding XMVD is satisfied in the XML document. Thirdly, we propose several normal forms for XML for different classes of XMVDs and keys and investigate their relationship with the elimination of redundancy. For arbitrary XMVDs we propose a normal form and prove that it is a sufficient condition for the elimination of redundancy. For a restricted class of XMVDs called ”hierarchical XMVDs”, we propose a normal form and prove that it is both a necessary and sufficient condition for the elimination of redundancy.

• Type: Conference
• Year: 2003
• Where: CAISE
• Authors: Millist W. Vincent, Jixue Liu
• Keywords: CAISE 2003, Main Contributions, Normal Form, XML Document