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338
A polygen model for Heterogeneous Database Systems: The Source Tagging Perspective
- WP # 3119-90 MSA. (Sloan School of Management, MIT
, 1990
"... This paper studies heterogeneous database systems from the multiple (poly) source @rrt) perspective. It aims at addressing issues such as “where is the data from ” and “which intermediate data sources were used to arrive at that data ”- issues which are critical to many users in utilizing informatio ..."
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Cited by 67 (16 self)
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This paper studies heterogeneous database systems from the multiple (poly) source @rrt) perspective. It aims at addressing issues such as “where is the data from ” and “which intermediate data sources were used to arrive at that data ”- issues which are critical to many users in utilizing information composed from multiple sources. Specifically, it presents a polygen model for resolving the Data Source Tagging and Intermediate Source Tagging problems. Secondly, it presents a data-driven query translation mechanism for mapping a polygen query into a set of local queries dynamically. A concrete example is also provided to exemplify polygen query processing. The significance of this paper lies not only in a precise characterization of a practical problem and a solution per se, but also in the establishment of a foundation for resolving many other critical research issues such as domain mismatch, semantic reconciliation, and data conflict amongst data retrieved from different sources. In a federated database environment with hundreds of databases, all of these issues are critical to their effective USt!. I.
Relational database: A practical foundation for productivity
- Communications of the ACM
, 1981
"... It is the Association's foremost award for technical contributions to the com-puting community. (2odd was selected by the A(2M General Technical Achievement Award (2ommittee for his "fundamental and continuing contributions to the theory and practice of database management systems. " ..."
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Cited by 64 (0 self)
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It is the Association's foremost award for technical contributions to the com-puting community. (2odd was selected by the A(2M General Technical Achievement Award (2ommittee for his "fundamental and continuing contributions to the theory and practice of database management systems. " The originator of the relational model for databases, (2odd has made further important contributions in the development of relational algebra, relational calculus, and normalization of relations. Edgar F. (2odd joined IBM in 1949 to prepare programs for the Selective Sequence Electronic Calculator. Since then, his work in computing has encom-passed logical design of computers (IBM 701 and Stretch), managing a computer center in Canada, heading the development ofone of the first operating systems with a general multiprogramming capability, contributing to the logic of self-reproducing automata, developing high level techniques for software specifica-tion, creating and extending the relational approach to database management, and developing an English analyzing and synthesizing subsystem for casual users of relational databases. He is also the author of Cellular Automata, n early volume in the A(2M Monograph Series.
Readings in object-oriented database systems
, 1990
"... This paper summarizes the interface, implementation, and use of a server process that is used as a backend by an object-oriented database system. This server is responsible for managing objects on secondary storage, managing transactions, and implementing a simple form of trigger. We sketch the inte ..."
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Cited by 63 (0 self)
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This paper summarizes the interface, implementation, and use of a server process that is used as a backend by an object-oriented database system. This server is responsible for managing objects on secondary storage, managing transactions, and implementing a simple form of trigger. We sketch the interface of this system and point out some of the more interesting implementation issues that were encountered in building it. Client processes communicate asynchronously with the server by message sending. The system is designed to be as efficient as possible since one of its clients is the GARDEN system, an object-oriented programming environment. GARDEN views both static and dynamic program pieces as objects. Our back-end server provides persistent and sharable storage for GARDEN. The paper includes an extended example of how GARDEN makes use of this resource. 1.
Disjunctive Deductive Databases
, 1994
"... Background material is presented on deductive and normal deductive databases. A historical review is presented of work in disjunctive deductive databases, starting from 1982. The semantics of alternative classes of disjunctive databases is reviewed with their model and fixpoint characterizations. Al ..."
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Cited by 59 (7 self)
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Background material is presented on deductive and normal deductive databases. A historical review is presented of work in disjunctive deductive databases, starting from 1982. The semantics of alternative classes of disjunctive databases is reviewed with their model and fixpoint characterizations. Algorithms are developed to compute answers to queries in the alternative theories using the concept of a model tree. Open problems in this area are discussed.
Logic and Databases: a 20 Year Retrospective
, 1996
"... . At a workshop held in Toulouse, France in 1977, Gallaire, Minker and Nicolas stated that logic and databases was a field in its own right (see [131]). This was the first time that this designation was made. The impetus for this started approximately twenty years ago in 1976 when I visited Gallaire ..."
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Cited by 58 (1 self)
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. At a workshop held in Toulouse, France in 1977, Gallaire, Minker and Nicolas stated that logic and databases was a field in its own right (see [131]). This was the first time that this designation was made. The impetus for this started approximately twenty years ago in 1976 when I visited Gallaire and Nicolas in Toulouse, France, which culminated in a workshop held in Toulouse, France in 1977. It is appropriate, then to provide an assessment as to what has been achieved in the twenty years since the field started as a distinct discipline. In this retrospective I shall review developments that have taken place in the field, assess the contributions that have been made, consider the status of implementations of deductive databases and discuss the future of work in this area. 1 Introduction As described in [234], the use of logic and deduction in databases started in the late 1960s. Prominent among the developments was the work by Levien and Maron [202, 203, 199, 200, 201] and Kuhns [1...
Gral: An Extensible Relational Database System for Geometric Applications
- PROC. OF THE 15TH INTL. CONF. ON VERY LARGE DATA BASES
, 1989
"... We describe the architecture of a relational database system that is extensible by user-defined data types and operations, including relation operations. The central concept is to use languages based on many-sorted algebra to represent queries as well as query execution plans. This leads to a simple ..."
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Cited by 49 (13 self)
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We describe the architecture of a relational database system that is extensible by user-defined data types and operations, including relation operations. The central concept is to use languages based on many-sorted algebra to represent queries as well as query execution plans. This leads to a simple and clean extensible system architecture, eases the task of an application developer by providing a uniform framework, and also simplifies rule-based optimization. As a case study the extensions needed for a geometric database system are considered.
Flexible Relation: An Approach for Integrating Data from Multiple, Possibly Inconsistent Databases
- In IEEE International Conference on Data Engineering
, 1995
"... In this work we address the problem of dealing with data inconsistencies while integrating data sets derived from multiple autonomous relational databases. The fundamental assumption in the classical relational model is that data is consistent and hence no support is provided for dealing with incons ..."
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Cited by 47 (1 self)
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In this work we address the problem of dealing with data inconsistencies while integrating data sets derived from multiple autonomous relational databases. The fundamental assumption in the classical relational model is that data is consistent and hence no support is provided for dealing with inconsistent data. Due to this limitation of the classical relational model, the semantics for detecting, representing, and manipulating inconsistent data have to be explicitly encoded in the applications by the application developer.
Using Dynamic Classes and Role Classes to Model Object Migration
, 1995
"... In this paper, we argue that object-oriented models must be able to represent three kinds of taxonomic structures: static classes, dynamic classes, and role classes, that behave differently with respect to object migration. If CAR is a static subclass of V EHICLE, then a vehicle that is not a car ..."
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Cited by 47 (2 self)
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In this paper, we argue that object-oriented models must be able to represent three kinds of taxonomic structures: static classes, dynamic classes, and role classes, that behave differently with respect to object migration. If CAR is a static subclass of V EHICLE, then a vehicle that is not a car can never migrate to the CAR subclass. On the other hand, if EMP loyee is a dynamic subclass of PERSON object class, then a PERSON that is not an employee may migrate to EMP . In both cases, an instance of the subclass is identical to an instance of the superclass. By contrast, if EMP is modeled as a role class of PERSON , then every employee differs from every person, but a PERSON instance can acquire one or more EMP instances as roles. The distinctions between the three kinds of classes are orthogonal, so that we can have, for example, dynamic subclasses of object or role classes, or role classes of dynamic or static classes. The paper is divided into two parts. In the first, infor...
Integrity control in relational database systems - an overview
- Data & Knowledge Engineering
, 1993
"... Grefen, P.W.P.J. and P.M.G. Apers, Integrity control in relational database systems- An overview, Data & ..."
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Cited by 45 (3 self)
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Grefen, P.W.P.J. and P.M.G. Apers, Integrity control in relational database systems- An overview, Data &
