Information integration using logical views

A number of ideas concerning information-integration tools can be thought o f as constructing answers to queries using views that represent the capabil ities of information sources. We review the formal basis of these technique s, which are closely related to containment algorithms for conjunctive quer ies and/or Datalog programs. Then Lye compare the approaches taken by AT&T Labs' "lnformation Manifold" and the Stanford "Tsimmis" project in these te rms. (C) 2000 Elsevier Science B.V. All lights reserved.