Stephen J. Hegner, 490317-0498, Bilaga till Ansökan Om Fft, Sida 1 Update Support in Component-based Database Systems

Modern database schemata are often large and complex, and a single user typically is afforded only limited access through a window, known as a view. The problem of supporting updates systematically through such views has long been known to be a difficult problem. Traditionally, the approach has been to limit the allowed updates to those which avoid or substantially limit so-called update anomalies; that is, changes which are not visible within the view itself. Unfortunately, the collection of such updates, which are defined by the so-called constant-complement strategy [BS81], [Heg04], is severely limited, and traditional extensions afford only a moderate increase in flexibility. In the research proposed here, a different approach to the view-update problem is taken. If a user of a given view cannot perform a given update without side effects, then that user must enlist the cooperation of other users, having update rights on other views, in such a way that all changes to the global database are visible to, and authorized by, at least one of the cooperating users.