Preliminary overview about relations QVT: Query/View/Transformation model transformation language

Despite of the well documentation of Model Driven Architecture (MDA) technique and the transformation language Query/View/Transformation Relation QVT (QVT-R) that provided by Object Management Group (OMG), we are finding there is no specific description about the execution engine for the QVT-R Transformation Language. In this paper we will try to provide a preliminary overview about the implementation (execution) model of QVT-R Language which we find it looks like prolog language code execution and this last one depends on Warren's Abstract Machine (WAM) to execute its' code.