Schema Mapping as Query Discovery

Renee J. Miller, Laura M. Haas, Mauricio A. Hernandez

To enable modern data intensive applications including data
warehousing, global information systems and electronic commerce, we
must solve the {\em schema mapping} problem in which a source (legacy)
database is mapped into a different, but fixed, target schema.  Schema
mapping involves the discovery of a query or set of queries that
transform the source data into the new structure.  We introduce an
interactive mapping creation paradigm based on {\em value
correspondences} that show how a value of a target attribute can be
created from a set of values of source attributes.  We describe the
use of the value correspondence framework in {\em Clio}, a prototype
tool for semi-automated schema mapping, and present an algorithm for
query derivation from an evolving set of value correspondences.