The maintenance of global integrity constraints in database federations is still a challenge since traditional integrity constraint management techniques cannot be applied to such a distributed management of data. In this paper we present a concept of global integrity maintenance by migrating the concepts of active database systems to a collection of interoperable relational databases. We introduce Active Component Systems which are able to interact with each other using direct connections established from within their database management systems. Global integrity constraints are decomposed into sets of partial integrity constraints, which are enforced directly by the affected Active Component Systems without the need of a global component.