A Comparison between Relational and Operational QVT Mappings

Model driven approaches raise the level of abstraction during software development, where the focus of the development process is no longer on programming, but instead on the creation of different models. The OMG is addressing this new methodology with their model driven architecture (MDA). The query/views/transformation (QVT) specification is part of the OMG´s MDA framework for combining declarative and imperative transformation languages between models. QVT-R uses a declarative (relational) approach to describe mappings between models, whereas QVT-O uses an imperative (operational) approach. Tools in this domain are still in their infancy and there exist no empirical study to compare QVT-O and QVT-R for complex application domains. In this paper we show how both QVT-R and QVT-O can be used to map byte code instructions for Microsoft´s .NET virtual machine to Sun Microsystem´s Java Virtual Machine. We provide an extensive comparison between QVT-O and QVT-R and offer some best practices for using either transformation language.