SPECIFYING GLOBAL BEHAVIOR IN DATABASE FEDERATIONS

We discuss the impact of locally implemented behaviour on global behav iour specification in a federation of object-oriented databases. In pa rticular, given a specification of an integrated view of a number of c omponent databases, we discuss the process of determining the global m ethods that are implicitly implemented by a given set of local methods on these component databases. To this end, we develop the notions of objectivity and subjectivity of local methods, indicating whether the execution of a local method affects the global view exactly as it affe cts the local database, behaviour equivalences between local methods, indicating whether local methods of different components have similar effect, and behaviour concurrences, indicating whether local methods r espond to the same event. These notions can be used as a basis for too ls supporting the engineering activity of specifying global behaviour in database federations. (C) 1998 Published by Elsevier Science Ltd. A ll rights reserved.