Representing UML snowflake diagram from integrating XML data using XML schema

We present a UML conceptual-level integration framework for supporting OLAP operations on diverse XML data sources. Our integration framework takes advantage of the constructs and relationships existing within XML schemas. Two processes are involved in our integration framework. The first one is to convert XML schemas into UML class diagrams. The second is to build a multidimensional model from the UML class diagrams. This paper focuses on the issues in the second process. We describe how to represent a multidimensional model using a UML snowflake diagram and how to represent the UML snow/lake diagram using XML schemas. Our advanced XML schema-based representation of a multidimensional model is used as metadata in our prototype system for processing OLAP queries. It elegantly holds the information within a UML snowflake diagram such as the retrieval path through which we can obtain the participating XML data sources for OLAP operations. To the best of our knowledge, we are the first people to apply the advantages of XML Schemas during integrating XML data sources for virtual OLAP and to propose an XML schema-based method for representing a UML snowflake diagram that integrates heterogeneous XML data sources.