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Advanced conceptual clustering and associated querying facilities in object-oriented databases

INTERNATIONAL JOURNAL OF SOFTWARE ENGINEERING AND KNOWLEDGE ENGINEERING 1999年第3期9卷 343-367页

作者： Fung, CW Li, Q Hong Kong Inst Vocat Educ Dept Comp Studies Tuen Mun Peoples R China City Univ Hong Kong Dept Comp Sci Kowloon Peoples R China

Conventional object-oriented database (OODB) systems follow a class-based approach to model real world entities and their relationships, which imposes several difficulties when more advanced "dynamic functions" are needed by the applications. One of such dynamic functions is conceptual clustering - the ability to dynamically group a set of existing objects together as a higher-level abstract object (called a "cluster"). The conceptual clustering model (CCM) that we have defined is an extension to current object-oriented models, which facilitates the modeling of dynamic, evolving, and/or ad hoc object clusters through a well-devised clustering mechanism that incorporates "roles". This paper presents the advanced features of CCM, along with its associated query language facilities devised for supporting general definition and access of clusters (and roles). An experimental prototype of the CCM has been constructed on top of a persistent object storage manager, running on a Sun4 workstation.

关键词： object-oriented databases conceptual clustering model dynamic roles query languages meta-level retrieval

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Towards a new role paradigm for object-oriented modeling 8th

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8th International Conference on object-oriented Information Systems, OOIS 2002

作者： Coulondre, Stéphane Libourel, Thérèse INSA de Lyon 20 Av Albert Einstein Villeurbanne Cedex69621 France LIRMM 161 rue Ada Montpellier Cedex 534392 France

ISBN: (纸本)9783540440888

In this paper, we consider the framework of "complex" information systems, related to biology, geographical information, multimedia, etc. Apart from being inherently complex, objects of these domains are evolutive, and related applications require more and more often to take into account this functionality, in the same way that reusability and extensibility currently are. What does it mean exactly to bring evolution in a formalism as a basic functionality? It means proposing, from the very first step of analysis and modeling, a way to express that future objects will, on one hand be persistent, and on the other hand be able to evolve through their life. This can be realized by allowing them to dynamically gain or loose some pieces of structure or behaviour aspects. This capability is practically added by taking into account the "role" notion as a complement of the notions of concept or class. In traditional class-based models, an object is linked to a single class (its generating abstract model), according to the mono-instanciation principle, and this class determines the object’s structure and behaviour during its lifespan. Indeed, some propositions, as that of P. Coad [6], suggested that objects could turn up to play several roles (*** 1), but the role is considered as a concept located on the same level as the class. © 2002, Springer-Verlag Berlin Heidelberg.

关键词： object-oriented databases

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Designing fuzzy relations in orthogonal persistence object-oriented database engines

Designing fuzzy relations in orthogonal persistence object-o...

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作者： Sicilia, Miguel Ángel Gutiérrez, José Antonio García, Elena Computer Science Dept. Carlos III University Avd. Universidad 30 28911 Leganés Madrid Spain Computer Science Dept. University of Alcalá Ctra. Barcelona km. 33.600 28871 Alcalá de Henares Madrid Spain

ISBN: (纸本)354000131X

Semantic relations between concepts or data are common modelling devices in various knowledge representation approaches. Fuzzy relations can be defined as fuzzy subsets of the cartesian product of a number of domains, extending the notion of crisp relation. Associations in object-oriented modelling - and more specifically in the Unified Modelling Language - can be interpreted as crisp relations on the classifiers they connect, and thus the concept of association can be extended to its fuzzy counterpart by representing a fuzzy relation on the classes involved in the association. In this paper, the resolution form of a fuzzy relation is described as a convenient way to represent fuzzy associations in object-oriented programming languages, thus enabling an efficient practical representation mechanism for them. Specific cases of fuzzy relations can also be dealt with by adding semantic constraints to fuzzy associations. One of the most interesting cases is that of similarity relations, which essentially generalize the notion of object equality to the fuzzy case. Fuzzy relations can be stored in orthogonally persistent object databases by using the described fuzzy association design, as illustrated in this paper with a case study that uses the db4o persistence engine. © Springer-Verlag 2002.

关键词： object-oriented databases

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A theorem prover-based analysis tool for object-oriented databases 5th

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Joint European Conference on Theory and Practice of Software (ETAPS 99)

作者： Spelt, D Even, S Univ Twente Ctr Telemat & Informat Technol NL-7500 AE Enschede Netherlands

ISBN: (纸本)3540657037

We present a theorem-prover based analysis tool for object-oriented database systems with integrity constraints. object-oriented database specifications are mapped to higher-order logic (HOL). This allows us to reason about the semantics of database operations using a mechanical theorem prover such as Isabelle or PVS. The tool can be used to verify various semantics requirements of the schema (such as transaction safety, compensation, and commutativity) to support the advanced transaction models used in workflow and cooperative work. We give an example of method safety analysis for the generic structure editing operations of a cooperative authoring system.

关键词： object-oriented databases

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Parallel sort-merge object-oriented collection join algorithms

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COMPUTER SYSTEMS SCIENCE AND ENGINEERING 2002年第3期17卷 145-158页

作者： Taniar, D Rahayu, JW Monash Univ Sch Business Syst Clayton Vic 3800 Australia La Trobe Univ Dept Comp Sci & Comp Engn Bundoora Vic 3083 Australia

One of the differences between relational and object-oriented databases (OODB) is that attributes in OODB can be of a collection type (e.g. sets, lists, arrays, and bags) as well as a simple type (e.g. integer, string). Consequently, explicit join queries in OODB may be based on collection attributes. We call this type of join Collection Join Queries. There are three different kinds of collection join queries, namely: Collection-Equi Join, Collection-Intersect join, and Sub-Collection Join. Basically, a collection-equi join query checks an equality of both collection operands, whereas a collection-intersect join query checks whether there is an intersection between the two join collection attributes. Sub-collection join queries check whether one collection is a sub-collection of the other. In this paper, we present parallel join algorithms for the above three collection join query types based on the sort-merge technique. Sonic of the proposed algorithms employ a nested-loop construct as well. We also outline the complexity of collection merging in the algorithm. Parallel join algorithms are normally composed of two stages, data partitioning and local join. For the data partitioning stage in collection-intersect and sub-collection join algorithms, we propose a 'Divide and Partial Broadcast' partitioning. The proposed join algorithms play an important role in parallel object-oriented query processing, due to their superiority over the conventional join methods, which are usually in a form of relational division, and also the inefficiency of original join predicates processing.

关键词： parallel query processing parallel join object-oriented join queries collection types object-oriented databases and sort-merge join

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Dynamic relationships and their propagation and concurrency semantics in object-oriented databases 4th

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4th International Workshop on Next Generation Information Technologies and Systems, NGITS 1999

作者： Sapir, Amir Gudes, Ehud Dept. of Mathematics and Computer Sciences Ben-Gurion University of the Negev Ben-Gurion Rd Beer Sheva Israel

ISBN: (纸本)3540662251

object-oriented databases has rich semantics, which enables the definition of various relationships among objects. Sharing levels and composition types necessitate the definition of whether, and to which extent, should a composed object propagate a message it receives, to its composing objects (propagation rules). Current solutions refer to a system with stable connections, so propagation values can be set at the design stage. Turning a compound object into a distributed collection of simpler ones, some of which are shared, necessitates defining exact protocols for transaction processing and concurrency control. The information system described contains complex relations, which vary on a daily basis. The paper examines the various update operations from relations creation point of view, and suggests an approach for defining these new relations and updating the propagation values dynamically. Thus, reflecting the changing nature of relations. © Springer-Verlag Berlin Heidelberg 1999.

关键词： object-oriented databases

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A survey of schema evolution in object-oriented databases 31

A survey of schema evolution in object-oriented databases

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31st International Conference on Technology of object-oriented Languages and Systems, TOOLS 1999

作者： Li, Xue School of Information Systems Technology and Management University of New South Wales Sydney2052 Australia

ISBN: (纸本)0769503934

Changes in the real world may require both the database population and the database schema to evolve. Particularly, this is the case in CAD/CAM and CASE database systems, in which the design objects constantly evolve in every aspect. On the other hand, the prototyping of a database design may also involve changes to both the structure and behavior of a schema. Unfortunately, most of the current systems offer little support for schema evolution. In this paper, we survey the recent development of the research in the schema evolution of objectoriented databases. The main issues in the current research are identified. © 1999 IEEE.

关键词： object-oriented databases

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PARALLEL SORT-HASH object-oriented COLLECTION JOIN ALGORITHMS FOR SHARED-MEMORY MACHINES

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Parallel Algorithms and Applications 2002年第2期17卷 85-126页

作者： David Taniar - E-mail: David.Taniar@infotech.monash.edu.au[a] J. Wenny Rahayu[b] [a] School of Business Systems Monash University Clayton Vic Australia [b] Department of Computer Science and Computer Engineering La Trobe University Bundarra Vic Australia

Collection join queries are join queries based on collection attributes (i.e. non-atomic attributes), which are common in object-oriented databases. We have identified three different kinds of collection join queries, namely;cullection-equijoin,collection-intersectjoin, andsub-collectionjoin. In this paper, we propose parallel join algorithms for these three collection join query types based on a combination of sort and hash methods, which we callparallel sort-hash, collection join algorithms. The proposed join algorithms play an important role in parallel object-oriented query processing, due to their superiority over the conventional join methods which are usually in a form of relational division, and also the inefficiency of the original join predicate processing. In our implementation of these algorithms on a shared-memory machine, we show that the combination between sort and hash methods is proven to be better than the conventional sort-merge and nested-loop based parallel join processing

关键词： Parallel query processing Parallel join object-oriented join queries Collection types object-oriented databases Parallel databases

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B-trees: Bearing Fruits of All Kinds 02

B-trees: Bearing Fruits of All Kinds

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Australasian Database Conference

作者： Beng Chin Ooi Kian-Lee Tan Department of Computer Science National University of Singapore 3 Science Drive 2 Singapore 117543

ISBN: (纸本)0909925836

Index structures are often used to support search operations in large databases. Many advanced database application domains such as spatial databases, multimedia databases, temporal databases, and object-oriented databases, call for index structures that are specially designed and tailored for the domains. Interestingly, in each of these domains, we find methods that are based on one distinct structure - the B-tree. Invented some thirty years ago, the B-tree has been challenged repeatedly, but has retained its competitiveness. In this paper, we first give a quick review of B-trees. We then present its adaptations to various domains. For each domain, we present representative B-tree-based structures and their search operations. We conclude that the B-tree is truly an ubiquitous structure that has stood the test of times with wide acceptance in many domains.

关键词： B-tree spatial databases multimedia databases high-dimensional databases main memory databases multimedia databases visual databases trees (mathematics) domains Phyla multi-dimensional database object-oriented databases Fruit

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Reengineering relational databases to object-oriented: Constructing the class hierarchy and migrating the data

Reengineering relational databases to object-oriented: Const...

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8th Working Conference on Reverse Engineering (WCRE)

作者： Alhajj, R Polat, F Univ Calgary Dept Comp Sci Calgary AB T2N 1N4 Canada

ISBN: (纸本)0769513034

The object-oriented data model is predicted to be the heart of the next generation of database systems. Users want to move from old legacy databases into applying this new technology that provides extensibility and flexibility in maintenance. However, a major limitation on the wide acceptance of object-oriented databases is the amount of time. and money invested on existing database applications, which are based on conventional legacy systems, Users do not want to loose the huge amounts of data present in conventional databases. This paper presents a novel approach to transform a given conventional database into an object-oriented database. It is assumed that the necessary characteristics of the conventional database to be re-engineered are known and available. The source of these characteristics might be the data dictionary and/or an expert in the given conventional database. We implemented a system that builds an understanding of a given conventional database by taking these characteristics as input and produces the corresponding object-oriented database as output. The system derives a graph that summarizes the conceptual model. Links in the graph are classified into inheritance links and aggregation links. This classification leads to the class hierarchy. Finally, we handle the migration of data from the conventional database to the constructed object-oriented database.

关键词： algorithms data migration forward engineering object-oriented databases reengineering of legacy databases relational databases

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