Date: Thursday Feb. 26, 2004 @ 1:30pm
Place: ASB 9705
Speaker: Eric Evangelista
A Knowledge-Level View of Consistent Query Answering
Of the numerous formal approaches that deal with database inconsistencies under integration (with respect to integrity constraints), all share the view that an integrity constraint is a statement about the world the database models. An alternative point of view, however, considers integrity constraints as statements about the knowledge the database has of it's domain. The result of this shift in perspective is a perspicacious representation not only of integrity constraints, but also of querying a possibly inconsistent database (applicable to both data warehousing and integration).
In embedding the above considerations in a powerful epistemic query language KL, we will discuss the issue of safety, and see how constraints and dependencies can be expressed in the idiom of KL. We will investigate how KL can be used to query a database inconsistent with it's integrity constraints, and then briefly consider directions for further research.