UQL: A UML-based Query Language for Integrated Data

A unified query language (UQL) in terms of UML is proposed based on the Object Constraint Language (OCL), which is a part of the UML specification. The semantics of the UQL, its scope, and interfaces based on this language are discussed. Processing of a UQL query is described including its transformation to XQuery, optimization, decomposition, execution of query parts against local data, and formation of the final result.