Using XQuery to describe mappings from global schemas to local data sources

This paper describes a database mediation system based on XML related technologies. Descriptions of its architecture, its key metadata and the processes that are used to answer user queries are included. The system uses XQuery to represent the mappings between the global schema and local schemas. XQuery is used to translate user queries on the global virtual database to queries on local data sources. The advantage of using XQuery over specialized logic or programming languages is improved standardization and a powerful descriptive capability for the data.