Incremental specification of views across databases

In an environment consisting of a large number of databases, it can no longer be reasonable to assume that construction of users´ views could rely on an a priori static partial or global schema integration. Approaches which are based on integrated mechanisms are obviously intractable (if not impossible) within a large size environment. The authors propose an approach where users are allowed to dynamically investigate information and incrementally specify their views. The idea is to use a functional approach to model the construction of views. Further, their approach provides a mechanism by which views adapt to the evolution of the information space. This mechanism relies on dynamic triggers to fulfil this goal