Models for Information Integration: Turning Local-as-View Into Global-as-View (2001)
| Venue: | In Proc. of Int. Workshop on Foundations of Models for Information Integration (10th Workshop in the series Foundations of Models and Languages for Data and Objects |
| Citations: | 9 - 2 self |
BibTeX
@INPROCEEDINGS{Calì01modelsfor,
author = {Andrea Calì and Giuseppe De Giacomo and Maurizio Lenzerini},
title = {Models for Information Integration: Turning Local-as-View Into Global-as-View},
booktitle = {In Proc. of Int. Workshop on Foundations of Models for Information Integration (10th Workshop in the series Foundations of Models and Languages for Data and Objects},
year = {2001}
}
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Abstract
There are basically two approaches for designing a data integration system. In the global-as-view approach, one defines the concepts in the global schema as views over the sources, whereas in the local-as-view approach, one characterizes the sources as views over the global schema. The goal of this paper is to verify whether we can transform a data integration system built with the local-as-view approach into a system following the global-as-view approach. We study the problem in a setting where the global schema is expressed in the relational model with inclusion dependencies, and the queries used in the integration systems (both the queries on the global schema, and the views in the mapping) are expressed in the language of conjunctive queries. The result we present is that such a transformation exists: we can always transform a local-as-view system into a global-as-view system such that, for each query, the set of answers to the query wrt the former is the same as the set of answers wrt the latter.
