Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10 5/3/83; site utcsrgv.UUCP Path: utzoo!utcsrgv!phyllis From: phyllis@utcsrgv.UUCP (Phyllis Eve Bregman) Newsgroups: ont.events Subject: DCS Seminar Schedule Message-ID: <1468@utcsrgv.UUCP> Date: Mon, 6-Jun-83 11:26:50 EDT Article-I.D.: utcsrgv.1468 Posted: Mon Jun 6 11:26:50 1983 Date-Received: Mon, 6-Jun-83 11:31:30 EDT Organization: CSRG, University of Toronto Lines: 21 UofT Department of Computer Science Seminar Schedule for the week of June 6th, 1983 Thursday, June 9th, 4:00 P.M., SF4101: Dr. Moshe Y. Vardi, Computer Science Department, Stanford University, Stanford, California: "On the semantics of updates in databases". ABSTRACT: We suggest here a methodology for updating databases with integrity constraints and rules for deriving inexplicit information. First we consider the problems of updating arbitrary theories by inserting into them or deleting from them arbitrary sentences. The solution involves two key ideas: when replacing an old theory by a new one we wish to minimize the change in the theory, and when there are several theories that involve minimal changes, we look for a new theory that reflects that ambiguity. The methodology is also adapted to updating databases, where different facts can carry different priorities, and to updating user views.