The formal step by step development of implementations from specifications is necessary to allow the incremental description of large software systems and hence split the software development process in manageable portions. Due to the complex notion of objects as units of structure and behavior, the refinement process has to be reconsidered in the object-oriented framework. Apart from refining structure the behavioral part gives rise to refine actions by transactions. Referring to information systems as application domain, concurrency control aspects come into play because of shared resources. We present an approach to