Eroc. Second Acm Sigact-sigmod Preliminary Report

1. Introduction We suggest here a methodology for updating data-The ability of the database user lo modify the con-bases with integrity constrain& and rules for deriving inex-tent of the database, the so-called updale operation, is fun-plicit information. First we consider the problem of damental to all database management systems. Since updating arbitrary theories by inserting inu, them or delet-many users do not deal with the entire conceptual database ing from them crbitrary sentences. The solution involves but only with a view of it, the problem of view updating, two key ideas: when replacing an old theory by a new one i.e., translating updates on a user view into updates of the we wish lo niuiiniize the change in the theory,, and when actual database, is of paramount importance, and has been there are several theories that involve minimal changes, we look for a new theory that reflects that ambiguity. The DB2, FS, J a 2. KD. Ke, KI, Os]. An assumption h a t methodology is also adapted to updating databases. where underlies all of these works is that only the view update different facts can carry different priorities, and lb updating issue is problematic (because of the ambiguity in translat-user views. ing view updates into database updates), and that the issue of updating the database directly is quite clear.