Foto Afrati, National Technical University of Athens
In various applications we need to access information that is stored in different schemas and use then it to answer queries. For this problem, we either store the data that we collect in a data warehouse or use mediators as an interface between the user and the various sources. In both cases, we may think of the various sources as views (either materialized or not). In the talk, we shall address the problem of how to answer queries using such views.