On Defining Functional Dependencies in XML Schema

The concept of functional dependency plays a foundational role in relational databases where it is used in integrity enforcement and database design. Similarly, functional dependencies in XML (XFDs) will play a centric role in providing richer data semantic information and normalizing XML data. In this paper, we present a new approach for defining XFDs on XML Schema. While showing how to extend XML Schema, we analyze the expressive power of our XFDs. We focus on supporting complex value (e.g. list, set) in our proposal. The satisfaction of XFDs in an XML document is defined in terms of the value equality. The checking algorithm for our proposal is given. Finally, we discuss the advantages of our XFDs over other previous work.