A Framework for Creating Global Schema Using Global Views from Distributed Heterogeneous Relational Databases in Multidatabase System

oai:ojs2.computerresearch.org:article/10000

Towards interoperability in heterogeneous database systems

Distributed heterogeneous databases consist of systems which differ physically and logically, containing different data models and data manipulation languages. Although these databases are independently created and administered they must cooperate and interoperate. Users need to access and manipulate data from several databases and applications may require data from a wide variety of independent databases. Therefore, a new system architecture is required to manipulate and manage distinct and multiple databases, in a transparent way, while preserving their autonomy. This report contains an extensive survey on heterogeneous databases, analysing and comparing the different aspects, concepts and approaches related to the topic. It introduces an architecture to support interoperability among heterogeneous database systems. The architecture avoids the use of a centralised structure to assist in the different phases of the interoperability process. It aims to support scalability, and to assure privacy and nfidentiality of the data. The proposed architecture allows the databases to decide when to participate in the system, what type of data to share and with which other databases, thereby preserving their autonomy. The report also describes an approach to information discovery in the proposed architecture, without using any centralised structure as repositories and dictionaries, and broadcasting to all databases. It attempts to reduce the number of databases searched and to preserve the privacy of the shared data. The main idea is to visit a database that either containsthe requested data or knows about another database that possible contains this data

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

Ontologies, contexts, and mediation : representing and reasoning about semantics conflicts in heterogeneous and autonomous systems

Cover title.Includes bibliographical references (p. 35-37).Cheng Hian Goh, Stuart E. Madnick, Michael D. Siegel

Crossâ Network Directory Service: Infrastructure to enable collaborations across distributed research networks

IntroductionExisting largeâ scale distributed health data networks are disconnected even as they address related questions of healthcare research and public policy. This paper describes the design and implementation of a fully functional prototype openâ source tool, the Crossâ Network Directory Service (CNDS), which addresses much of what keeps distributed networks disconnected from each other.MethodsThe set of services needed to implement a Crossâ Directory Service was identified through engagement with stakeholders and workgroup members. CNDS was implemented using PCORnet and Sentinel network instances and tested by participating data partners.ResultsWeb services that enable the four major functional features of the service (registration, discovery, communication, and governance) were developed and placed into an openâ source repository. The services include a robust metadata model that is extensible to accommodate a virtually unlimited inventory of metadata fields, without requiring any further software development. The user interfaces are programmatically generated based on the contents of the metadata model.ConclusionThe CNDS pilot project gathered functional requirements from stakeholders and collaborating partners to build a software application to enable crossâ network data and resource sharing. The two partnersâ one from Sentinel and one from PCORnetâ tested the software. They successfully entered metadata about their organizations and data sources and then used the Discovery and Communication functionality to find data sources of interest and send a crossâ network query. The CNDS software can help integrate disparate health data networks by providing a mechanism for data partners to participate in multiple networks, share resources, and seamlessly send queries across those networks.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/149237/1/lrh210187.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/149237/2/lrh210187_am.pd

CORBA: a middleware for an heterogeneous cooperative system

Two kinds of heterogeneities interfere with the integration of different information sources, those in systems and those in semantics. They generate different problems and require different solutions. This paper tries to separate them by proposing the usage of a distinct tool for each one (i.e. CORBA and BLOOM respectively), and analizing how they could collaborate. CORBA offers lots of ways to deal with distributed objects and their potential needs, while BLOOM takes care of the semantic heterogeneities. Therefore, it seems promising to handle the system heterogeneities by wrapping the components of the BLOOM execution architecture into CORBA objects.Postprint (published version