Schema architecture and their relationships to transaction processing in distributed database systems

We discuss the different types of schema architectures which could be supported by distributed database systems, making a clear distinction between logical, physical, and federated distribution. We elaborate on the additional mapping information required in architecture based on logical distribution in order to support retrieval as well as update operations. We illustrate the problems in schema integration and data integration in multidatabase systems and discuss their impact on query processing. Finally, we discuss different issues relevant to the cooperation (or noncooperation) of local database systems in a heterogeneous multidatabase system and their relationship to the schema architecture and transaction processing

A database management capability for Ada

The data requirements of mission critical defense systems have been increasing dramatically. Command and control, intelligence, logistics, and even weapons systems are being required to integrate, process, and share ever increasing volumes of information. To meet this need, systems are now being specified that incorporate data base management subsystems for handling storage and retrieval of information. It is expected that a large number of the next generation of mission critical systems will contain embedded data base management systems. Since the use of Ada has been mandated for most of these systems, it is important to address the issues of providing data base management capabilities that can be closely coupled with Ada. A comprehensive distributed data base management project has been investigated. The key deliverables of this project are three closely related prototype systems implemented in Ada. These three systems are discussed

Composite information systems : resolving semantic heterogeneities

"March 1991."Includes bibliographical references (p. 14-16).Michael Siegel, Stuart Madnick, Amar Gupta

Open issues in semantic query optimization in relational DBMS

After two decades of research into Semantic Query Optimization (SQO) there is clear agreement as to the efficacy of SQO. However, although there are some experimental implementations there are still no commercial implementations. We first present a thorough analysis of research into SQO. We identify three problems which inhibit the effective use of SQO in Relational Database Management Systems(RDBMS). We then propose solutions to these problems and describe first steps towards the implementation of an effective semantic query optimizer for relational databases

Semantic interoperability through context interchange : representing and reasoning about data conflicts in heterogeneous and autonomous systems

Cover title.Includes bibliographical references (p. 24-25).Supported in part by ARPA, International Financial Services Research Center (IFSRC), PROductivity From Information Technology (PROFIT), National University of Singapore, and USAF/Rome Laboratory. F30602-93-C-0160Cheng Hian Goh, Stuart E. Madnick, Michael D. Siegel

Estrategia de procesamiento y optimización de consultas en un gestor de bases de datos federadas

Based on BLOOM (BarceLona Object-Oriented Model), we propose to establish a global query processing strategy in the Federated Query Manager. First, the developing mechanism constructs a tree, which has nodes that initially represent explicit joins between federated classes and that are decomposed, into implicit joins between classes in the Component Schemas. Consequently, different heuristic techniques are performed in order to optimise the decomposition process, which generate one or more Execution Plans (EP). After that, the EP are analysed to get the optimum. The objective function of this strategy is to choose an execution plan with the least total resource usage and the best response time. Finally, the consolidation of partial results is carried out maintaining the federated result in the root node.Basado en el Proyecto BLOOM (BarceLona Object- Oriented Model), se propone establecer una estrategia de procesamiento de la consulta global dentro del Gestor de Consultas Federado. Primero, se construye un árbol cuyos nodos inicialmente representan joins explícitos entre clases federadas y los cuales son descompuestos en joins implícitos entre clases en los esquemas componentes. Posteriormente, diferentes técnicas heurísticas optimizan el proceso de descomposición, las cuales generan uno o mas Planes de Ejecución (PE). Después, éstos PE son analizados para obtener el optimo. La función objetiva de esta estrategia es encontrar un plan de ejecución con el menor uso de recursos y el mejor tiempo de respuesta. Finalmente, la consolidación de resultados parciales se lleva a cabo manteniendo la respuesta federada en el nodo raíz.Postprint (published version

Global Semantic Integrity Constraint Checking for a System of Databases

In today’s emerging information systems, it is natural to have data distributed across multiple sites. We define a System of Databases (SyDb) as a collection of autonomous and heterogeneous databases. R-SyDb (System of Relational Databases) is a restricted form of SyDb, referring to a collection of relational databases, which are independent. Similarly, X-SyDb (System of XML Databases) refers to a collection of XML databases. Global integrity constraints ensure integrity and consistency of data spanning multiple databases. In this dissertation, we present (i) Constraint Checker, a general framework of a mobile agent based approach for checking global constraints on R-SyDb, and (ii) XConstraint Checker, a general framework for checking global XML constraints on X-SyDb. Furthermore, we formalize multiple efficient algorithms for varying semantic integrity constraints involving both arithmetic and aggregate predicates. The algorithms take as input an update statement, list of all global semantic integrity constraints with arithmetic predicates or aggregate predicates and outputs sub-constraints to be executed on remote sites. The algorithms are efficient since (i) constraint check is carried out at compile time, i.e. before executing update statement; hence we save time and resources by avoiding rollbacks, and (ii) the implementation exploits parallelism. We have also implemented a prototype of systems and algorithms for both R-SyDb and X-SyDb. We also present performance evaluations of the system

Financial Information Mediation: A Case Study of Standards Integration for Electronic Bill Presentment and Payment Using the COIN Mediation Technology

Each player in the financial industry, each bank, stock exchange, government agency, or insurance company operates its own financial information system or systems. By its very nature, financial information, like the money that it represents, changes hands. Therefore the interoperation of financial information systems is the cornerstone of the financial services they support. E-services frameworks such as web services are an unprecedented opportunity for the flexible interoperation of financial systems. Naturally the critical economic role and the complexity of financial information led to the development of various standards. Yet standards alone are not the panacea: different groups of players use different standards or different interpretations of the same standard. We believe that the solution lies in the convergence of flexible E-services such as web-services and semantically rich meta-data as promised by the semantic Web; then a mediation architecture can be used for the documentation, identification, and resolution of semantic conflicts arising from the interoperation of heterogeneous financial services. In this paper we illustrate the nature of the problem in the Electronic Bill Presentment and Payment (EBPP) industry and the viability of the solution we propose. We describe and analyze the integration of services using four different formats: the IFX, OFX and SWIFT standards, and an example proprietary format. To accomplish this integration we use the COntext INterchange (COIN) framework. The COIN architecture leverages a model of sources and receivers’ contexts in reference to a rich domain model or ontology for the description and resolution of semantic heterogeneity.Singapore-MIT Alliance (SMA