RWTH Aachen University
Schema evolution has recently gained much interest in both research and practice. However, most of the existing works deal with separate aspects of the problem such as evolution of XML (eXtensible Markup Language) schemas or evolution of conceptual schemas. In addition, all of them view the problem only from the perspective of a single application. In this paper, the authors show that schema evolution has several different levels at which it can be performed and that are highly related. Secondly, they show that schema evolution is not the problem of a single application, but multiple applications having the same problem domain can influence each other as well.