Multidirectional Transformations and Synchronisations (Dagstuhl Seminar 18491)

Bidirectional transformations (bx) are a mechanism for maintaining the consistency of two (or more) related sources of information, such as models in model-driven development, database schemas, or programs. Bx technologies have been developed for practical engineering purposes in many diverse fields. Different disciplines such as programming languages, graph transformations, software engineering, and databases have contributed to the concepts and theory of bx. However, so far, most efforts have been focused on the case where exactly two information sources must be kept consistent; the case of more than two has usually been considered as an afterthought. In many practical scenarios, it is essential to work with more than two information sources, but the community has hardly started to identify and address the research challenges that this brings. Driven by the practical needs and usage scenarios from industry, this Dagstuhl Seminar aimed to identify the challenges, issues and open research problems for multidirectional model transformations and synchronisations and sketch a road map for developing relevant concepts, theories and tools. The report contains an executive summary of the seminar, reports from its working groups, as well as descriptions of industrial and academic case studies that motivated the discussions.