Model transformation is a key technique used in model-driven architecture. As the name QVT indicates, the OMG standard covers transformations, views and queries together. Model queries and model views can be seen as special kinds of model transformation, provided that we use a suitably broad definition of model transformation: a model transformation is a program which operates on models.
The QVT standard defines three model transformation languages. All of them operate on models which conform to MOF 2.0 metamodels; the transformation states which metamodels are used. A transformation in any of the three QVT languages can itself be regarded as a model, conforming to one of the metamodels specified in the standard. The QVT standard integrates the OCL 2.0 standard and also extends it with imperative features.
QVT-Operational is an imperative language designed for writing unidirectional transformations.
QVT-Relations is a declarative language designed to permit both unidirectional and bidirectional model transformations to be written. A transformation embodies a consistency relation on sets of models. Consistency can be checked by executing the transformation in checkonly mode; the transformation then returns True if the set of models is consistent according to the transformation and False......