On-Line Analytical Processing Queries for extensible Mark-up Language

摘要

extensible Mark-up Language (XML) is emerged as a standard to exchange data over the Web. A large amount of heterogeneous data is now available on the Web in different sources; these data are generally represented or published in XML format. A XML data warehouse is an integrated repository of different XML data sources enabling analysts to gain insight through fast access to a variety of possible views on XML data which are organized in a dimensional model. XML data warehouse can be queried by On-Line Analytical Processing (OLAP) queries. This study proposes XML data cube model which is a well-founded approach to represent OLAP data using XML. XML data cube enables the use of external XML data for selection and grouping. Recently a SQL-like query language XRQL is proposed to query XML data. The XRQL queries capture the flavour of SQL queries while offering constructs for navigation, XML data construction and grouping. This study shows how OLAP queries can be expressed by using XRQL in a natural way and extends XRQL by GROUP BY CUBE and GROUP BY ROLLUP operators to enable analysts to express more complex OLAP queries on XML data cube.