The Piazza Peer Data Management System

Abstract

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. This material is posted here with permission of the IEEE. Such permission of the IEEE does not in any way imply IEEE endorsement of any of the University of Pennsylvania's products or services. Internal or personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution must be obtained from the IEEE by writing to pubs-permissions@ieee.org. By choosing to view this document, you agree to all provisions of the copyright laws protecting it. Abstract-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. Author(s)Alon

Consistency and trust in peer data exchange systems

“…also (Halevy et al 2004)). Mappings relate two conjunctive queries that are expressed in terms of the schemas of two disjoint sets of peers.…”

Clio: Schema Mapping Creation and Data Exchange

“…Declarative schema mapping formalisms have been used to provide formal semantics for data exchange [19], data integration [33], peer data management [28,13,25], pay-as-you-go integration systems [45], and model management operators [8]. A whole area of model management has focused on such issues as mapping composition [35,21,40] and mapping inverse [18,22].…”

“…The generation of efficient queries for data exchange is not considered in work like Piazza [28] and HePToX [13] which instead focus on query generation for data integration. More recently, in model management [37,10], query or code generation for data exchange has been considered for embedded dependencies.…”

New Frontiers in Business Intelligence: Distribution and Personalization

“…Peer Data Management Systems (PDMSs [7]) have been proposed in the literature as architectures to support sharing of operational data across networks of peers while guaranteeing peer autonomy, based on interlinked semantic mappings that mediate between the heterogeneous schemata exposed by peers [10]. The architecture we outlined in the previous section is in line with the PDMS infrastructure, but requires a number of specific issues -mostly related to the multidimensional nature of the information exchanged-to be faced:…”