Common Pitfalls of Using QVT Relations - Graphical Debugging as Remedy

OMG’s Model-Driven Architecture (MDA) has emerged as a new approach for the development of software. For this, the Query/View/Transformation (QVT) standard plays a central role, since it allows for the specification of model transformations. Nevertheless, until now, QVT-tool support in general and debugging support in particular in the context of MDA are rather limited, supposable being a reason, that the adoption of QVT in practice has not yet been achieved. We therefore propose graphical debugging for the QVT Relations language based on TROPIC - a model transformation approach on the basis of Coloured Petri Nets. By enabling debugging on the TROPIC level, one gains several advantages when developing transformations. Firstly, debugging can take place at a high level of abstraction. Secondly, it serves for explicating the operational semantics of a transformation. Thirdly, it provides a homogenous representation of all transformation artifacts. As a first step towards QVT debugging, this paper aims at a deeper understanding of the operational semantics of QVT, classifying common pitfalls by using QVT and discussing how they may be identified at the TROPIC level.