Departmental Papers (CIS)

Date of this Version

July 2004

Document Type

Journal Article


Copyright 2004 IEEE. Reprinted from IEEE Transactions on Knowledge and Data Engineering, Volume 16, Issue 7, July 2004, pages 787-798.
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Intuitively, data management and data integration tools should be well-suited for exchanging information in a semantically meaningful way. Unfortunately, they suffer from two significant problems: They typically require a comprehensive schema design before they can be used to store or share information and they are difficult to extend because schema evolution is heavyweight and may break backward compatibility. As a result, many small-scale data sharing tasks are more easily facilitated by non-databaseoriented tools that have little support for semantics. The goal of the peer data management system (PDMS) is to address this need: We propose the use of a decentralized, easily extensible data management architecture in which any user can contribute new data, schema information, or even mappings between other peers’ schemas. PDMSs represent a natural step beyond data integration systems, replacing their single logical schema with an interlinked collection of semantic mappings between peers’ individual schemas. This paper describes several aspects of the Piazza PDMS, including the schema mediation formalism, query answering and optimization algorithms, and the relevance of PDMSs to the Semantic Web.


peer data management, data integration, schema mediation, web, databases



Date Posted: 16 November 2004

This document has been peer reviewed.