View maintenance after view synchronization

While current view technology assumes that information systems (ISs) do not change their schemas, our Evolvable View Environment (EVE) project addresses this problem by evolving the view definitions affected by IS schema changes, which we call view synchronization. In EVE, the view synchronizer rewrites the view definitions by replacing view components with suitable components from other ISs. However, after such a view redefinition process, the view extents, if materialized, must also be brought up to date. In this paper, we propose strategies to address this incremental adaptation of the view extent after view synchronization. One key idea of our approach is to regard the complex changes done to a view definition after synchronization as an atomic unit; another is to exploit knowledge of how the view definition was synchronized, especially the containment information between the old and new views. Our techniques would successfully adapt views under the unavailability of base relations, while currently known maintenance strategies from the literature would fail