Multivalued dependencies for XML

The wide use of XML has necessitated the XML document semantically richer. The integrity constraints play an important role in relational world. And the integrity constraints for XML have been widely investigated over the past few years. There are a few researches on multivalued dependencies for XML (XMVDs) and most of them are based on paths. In this paper, we propose a novel approach for defining XMVDs in XML Schema. We introduce “participant” to organize the involved information items that are divided into three groups called determinant, dependency and codependency in our extension. Two existing components, selector and field, are used to locate the information items, which uses restricted XPath as path description language. In particular, we extend the semantics of the field component to support a set (list) of nodes and node with complex type. Related issues are discussed, such as comparing element nodes with complex type.