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DESIGN AND IMPLEMENTATION OR ROCK-AND-ROLL - A DEDUCTIVE object-oriented DATABASE SYSTEM

INFORMATION SYSTEMS 1995年第3期20卷 185-211页

作者： BARJA, ML FERNANDES, AAA PATON, NW WILLIAMS, MH DINN, A ABDELMOTY, AI Department of Computing and Electrical Engineering Heriot-Watt University Edinburgh EH14 4AS UK

This paper presents an approach to the development of a deductive object-oriented database system, describing the key design decisions and their consequences for implementation. The approach is novel, in that it integrates an object-oriented database system manipulated using an imperative programming language (ROCK) with a logic language for expressing queries and methods (ROLL). The integration is made seamless by deriving both the imperative and logic languages from a single formally defined data model, thereby avoiding impedance mismatches when they are integrated.

关键词： DEDUCTIVE object-oriented databases DEDUCTIVE databases object-oriented databases DATABASE PROGRAMMING LOGIC PROGRAMMING

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The OODB path-method generator (PMG) using access weights and precomputed access relevance

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VLDB JOURNAL 1998年第1期7卷 25-47页

作者： Mehta, A Geller, J Perl, Y Neuhold, E Polytech Univ CALC Brooklyn NY 11201 USA New Jersey Inst Technol CIS Dept Newark NJ 07102 USA GMD IPSI D-6100 Darmstadt Germany

A path-method is used as a mechanism in object-oriented databases (OODBs) to retrieve or to update information relevant to one class that is not stored with that class but with some other class. A path-method is a method which traverses from one class through a chain of connections between classes and accesses information at another class. However, it is a difficult task for a casual user or even an application programmer to write path-methods to facilitate queries. This is because it might require comprehensive knowledge of many classes of the conceptual schema that are not directly involved in the query, and therefore may not even be included in a user's (incomplete) view about the contents of the database. We have developed a system, called path-method generator (PMG), which generates path-methods automatically according to a user's database-manipulating requests. The PMG offers the user one of the possible path-methods and the user verifies from his knowledge of the intended purpose of the request whether that path-method is the desired one. If the path method is rejected, then the user can utilize his now increased knowledge about the database to request (with additional parameters given) another offer from the PMG. The PMG is based on access weights attached to the connections between classes and precomputed access relevance between every pair of classes of the OODB. Specific rules for access weight assignment and algorithms for computing access relevance appeared in our previous papers [MGPF92, MGPF93, MGPF96]. In this paper, we present a variety of traversal algorithms based on access weights and precomputed access relevance. Experiments identify some of these algorithms as very successful in generating most desired path-methods. The PMG system utilizes these successful algorithms and is thus an efficient tool for aiding the user with the difficult task of querying and updating a large OODB.

关键词： object-oriented databases path-method OODB queries access weight access relevance traversal algorithms

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object-oriented DATABASE-MANAGEMENT SYSTEMS - EVOLUTION AND PERFORMANCE ISSUES

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COMPUTER 1993年第2期26卷 48-&页

作者： HURSON, AR PAKZAD, SH CHENG, JB IBM CORP RES TRIANGLE PKNC

Several research prototypes and commercial object-oriented database management systems (DBMSs) that emphasize the representation and manipulation of complex objects are reviewed. It is argued that clustering and buffering schemes tailored to typical complex object operations offer the best near-term means of improving the performance of databases and that research in clustering and buffering should address recent advances in disk technology: optical and parallel disks. The object-oriented DBMSs reviewed are Orion, Iris, GemStone, Encore, Ontos, Versant, and objectStore

关键词： Encore GemStone Iris objectStore Ontos Orion Versant buffering schemes clustering commercial object-oriented database management systems complex objects database theory disk technology near-term means object-oriented DBMSs object-oriented databases parallel disks performance issues research prototypes software packages typical complex object operations

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A graph-theoretic model for optimizing queries involving methods

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VLDB JOURNAL 2001年第4期9卷 327-343页

作者： Lee, C Shih, CS Chen, YH Natl Cheng Kung Univ Inst Informat Engn Tainan 70101 Taiwan Natl Chiayi Univ Dept Comp Sci & Informat Engn Chiayi Taiwan

Traditional algorithms for optimizing the execution order of joins are no more valid when selections and projections involve methods and become very expensive operations. Selections and projections could be even more costly than joins such that they are pulled above joins, rather than pushed down in a query tree. In this paper, we take a fundamental look at how to approach query optimization from a top-down design perspective, rather than trying to force one model to fit into another. We present a graph model which is designed to characterize execution plans. Each edge and each vertex of the graph is assigned a weight to model execution plans. We also design algorithms that use these weights to optimize the execution order of operations. A cost model of these algorithms is developed. Experiments are conducted on the basis of this cost model. The results show that our algorithms are superior to similar work proposed in the literature.

关键词： method query object-oriented databases query optimization graph model spanning tree

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The efficacy of commutativity-based semantic locking in a real-world application

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IEEE TRANSACTIONS ON KNOWLEDGE AND DATA ENGINEERING 2008年第3期20卷 427-431页

作者： Wu, Paul Fekete, Alan Rohm, Uwe Univ Sydney Sch Informat Technol Sydney NSW 2006 Australia

While the dominant approach to persistent storage in practice is to use a relational DBMS, there are some specialist applications that rely on object stores. The performance of these applications depends on the efficiency of the object store's concurrency control mechanism. Today's predominant concurrency control mechanism is strict two-phase object locking. In the 1980s, an interesting alternative was developed: commutativity-based semantic locking. In theory, it can outperform traditional locking schemes in certain scenarios with appropriate commutativity potential. In this paper, we study the real-world performance of different locking strategies in a particular industrial application from the telecommunications sector. We compare object-based locking and commutativity-based semantic locking. We found that, in this application, semantic locking performs equally to, but no better than, object locking in reasonable mixes of real-world transactions, and that it only outperforms in a deliberately contrived mix.

关键词： concurrency control persistent object systems object-oriented databases transaction processing

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How UML is used

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COMMUNICATIONS OF THE ACM 2006年第5期49卷 109-113页

作者： Dobing, B Parsons, J Univ Lethbridge Fac Management Lethbridge AB T1K 3M4 Canada Mem Univ Newfoundland Fac Business Adm St John NF Canada

The Unified Modeling Language (UML) emerged in the mid-1990sthrough the combination of previously competing object-oriented (OO) software engineeringmethods developed by Booch, Jacobson et al. [6] Rumbaugh et al. [8], and others. Control over itsformal evolution was placed in the hands of the object Management Group (***), and thelanguage has become widely accepted as a modeling standard for OO software development. A largenumber of practitioner articles and books, and some contributions by academic researchers,have been devoted to articulating various aspects of the language, including guidelines for usingit. UML per se is a language, not a methodology, so it is not surprising these guidelines are notalways consistent.

关键词： Software engineering System analysis Control theory (Mathematics) object-oriented databases Computer programming management Computer software developers UML (Computer science)

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THE object REVOLUTION - HOW COM TECHNOLOGY IS CHANGING THE WAY WE DO BUSINESS

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COMPUTING & CONTROL ENGINEERING JOURNAL 1995年第3期6卷 108-112页

作者： GANI, S PICURI, P Union Bank of Switzerland Zurich Switzerland

Today, advances in personal computing are helping corporations compete in a dynamic, global economy. Businesses, however, need new ways to deliver information systems in a faster, more cost-effective manner. object technology, in the form of COM will help businesses meet these needs. This article presents GDES for client/server computing based on OLE and objectBroker. GDES is a huge step forward in UBS's client/server computing strategy. It serves as a blueprint for future UBS applications where information is stored on a variety of dissimilar computers and databases.

关键词： microcomputer applications Union Bank of Switzerland personal computing GDES OLE client/server computing General Data Extract Service object-oriented programming object-oriented methods objectBroker client-server systems business data processing Financial computing dynamic global economy Common object Model Formal methods information systems delivery object Linking and Embedding object technology databases object-oriented databases Business and administration COM technology business needs bank data processing Component object Model management information systems Business applications of IT

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Genericity in Java: persistent and database systems implications

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VLDB JOURNAL 2008年第4期17卷 847-878页

作者： Alagic, Suad Royer, Mark Univ So Maine Dept Comp Sci Portland ME 04103 USA

Lack of parametric polymorphism has been a major obstacle for making Java a viable database programming language. Regrettably, a recently accepted solution for genericity in Java 5.0 has far-reaching negative implications for persistent and database systems because of static and dynamic type violations. Severe implications occur in typical database transactions when processing a variety of database collections. Well-known approaches to persistence in Java, including Java's own persistence mechanism, do not perform correctly due to incorrect dynamic type information that gets promoted to persistence along with objects. Dynamic checking of types of objects fetched from the persistent store may now lead to unexpected type violations. Further problems occur in reflective transactions as Java Core Reflection now allows dynamic type violations without detecting them or throwing standard exceptions. All of this shows that extending Java with parametric polymorphism has not made Java a more viable database programming language. Both legacy systems, such as those based on the Java binding of the ODMG or JDO, and future Java-related persistent and database technologies will be affected. The source of these problems is in an implementation idiom called type erasure. This paper provides formal proofs of the above implications of type erasure along with specific samples of code in Java 5.0 illustrating these violations. The limitations of the virtual platform and extensions required for persistent systems to solve this problem are also elaborated.

关键词： Java object persistence type systems object-oriented databases transactions reflection virtual platforms

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Powerdomain of paths for representing object structures

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Fundamenta Informaticae 1998年第2期33卷 121-148页

作者： Pankowski, Tadeusz Department of Control Robotics and Computer Science Poznan University of Technology Poznan Poland. e-mail:

A new method for viewing and manipulating identity-based object structures is proposed. The method is founded on the viewing the object structure as an object graph which in turn is represented as a set of paths. Over a power set of paths we construct a powerdomain which forms a lattice with well-defined meet and join operations. In our construction of the powerdomain of paths we combine the Hoare ordering (appropriate for ordering of tuple objects) with the Smyth ordering (appropriate for ordering of set objects) into a new ordering appropriate for set of paths capturing information conveyed by both tuple and set objects. The approach allows to deal with incomplete tuple objects as well as with partially described sets. The goal of the powerdomain construction is to provide a semantic domain for a path calculus language [20], where path calculus variables range over paths and path calculus queries give sets of paths as their answers.

关键词： object-oriented databases complex objects powerdomains object graphs

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QUERY CLASSIFICATION IN object-oriented ENGINEERING DESIGN SYSTEMS

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COMPUTER-AIDED DESIGN 1994年第2期26卷 127-136页

作者： SAMARAS, G SPOONER, D HARDWICK, M RENSSELAER POLYTECH INST DEPT COMP SCITROYNY 12180 RENSSELAER POLYTECH INST RENSSELAER DESIGN RES CTRTROYNY 12180

A query model for object-oriented engineering design systems exhibits characteristics that are quite different from those found in relational models. An engineering query model should take into account the fundamental concepts and requirements of interactive engineering applications that are not found in traditional applications. For example, engineering systems deal with large volumes of data of high complexity, with recursive structures and rich semantic properties. Similarly, engineering systems require the support of 'long transactions', as opposed to the 'short transactions' found in traditional relational-database systems. These differences have an interesting effect on the complexity of and strategy for query evaluation in engineering systems. The paper provides a framework for the classification of queries in engineering design systems. Engineering queries are classified into several categories on the basis of their semantics and complexity, and the impact of these queries on the architecture of an object-oriented engineering design system is shown.

关键词： ENGINEERING QUERIES object QUERIES ENGINEERING databases QUERY CLASSIFICATION object-oriented databases

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