Towards a Foundation for XML Document Databases

This paper develops a theoretical framework for modeling and managing XML documents by employment of Declarative Description (DD) theory. In the framework, the definition of an XML element is formally extended by incorporation of variables in order to represent inherent implicit information and enhance its expressive power. An XML document - a set of XML elements - is simply modeled as an XML declarative description which consists of object descriptions, representing XML elements in the document, and relationship descriptions, specifying relationships among the elements as well as integrity constraints. DTDs and complex queries can also be expressed and evaluated.