Well-Founded Views in Constraint Databases: Incremental Materialization and Maintenance

In this paper, we study the problem of incremental maintenance of materialized views when the view deenitions are allowed to contain: (a) constraints, and (b) well-founded modes of negation. A materialized view in our framework consists of a set of constrained non-ground tuples. We develop incremental algorithms to compute such non-ground materialized well-founded views, extending previous results of Gottlob et. al. and Eiter et. al. With respect to (b), previous attempts at view maintenance have been limited to the case when stratiied negation is used. In contrast, in this paper, we allow arbitrary (stratiied and/or unstratiied) usage of negation. Recursive views are also allowed. We develop a view maintenance algorithm called WF-Red for handling updates in such cases. WF-Red takes two parameters as input { a list of insertions and a list of deletions. To handle insertions, the list of deletions is kept empty and vice-versa. The algorithm correctly handles both insertions and deletions to the materialized view.