A graphical environment to query XML data with XQuery

Abstract

XQuery, the standard query language for XML, is increasingly popular among computer scientists with a SQL background, since queries in XQuery and SQL require comparable skills to be formulated. However, the number of these experts is limited, and the availability of easier XQuery "dialects" could be extremely valuable. With this motivation in mind, we designed XQBE, a dialect of XQuery inspired by the QBE language (query by example). QBE, initially proposed as an alternative to SQL, has then become popular as the user-friendly query language supported by MS Access. XQBE starts from hierarchical structures, coherent with the hierarchical nature of XML, and uses one or more structures to denote the input documents, and one structure to denote the XML document produced in output. These structures are annotated to express selection predicates; explicit bindings connecting the nodes of these structures visualize the input/output mappings.