 His research work on developing query languages and algorithms for managing semistructured and XML data has been highly influential in the data management research community.He has helped shape XML query languages such as XML-QL and Strudel, which influenced the subsequent design of the standard XQuery language.His work on XML-relational mapping in the context of the STORED and SilkRoute projects built the foundations of the standard techniques that are now used for storing XML data in commercial database systems.