Validating Constraints with Partial Information: Research Overview

We are interested in the problem of validating the consistency of integrity constraints when data is modi ed. In particular, we consider how constraints can be checked with only \partial information". Partial information may include: (1) the constraint speci cations only, (2) the constraint speci cations and the modi ed data, or (3) the constraint speci cations, the modi ed data, and portions of the existing data. Methods for constraint checking with partial information can be much more e cient than traditional constraint checking methods (e.g. because work is done at compile time, or because less data is accessed). Partial information methods also enable constraint checking in scenarios where traditional constraint checking methods fail (e.g. in distributed environments where not all data is accessible). We explain how existing methods and results for query containment and for independence can be applied to problems (1) and (2) above, and we give an overview of our research into problem (3).