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Performance analysis of parallel query processing algorithms for object-oriented databases

IEEE TRANSACTIONS ON KNOWLEDGE AND DATA ENGINEERING 2000年第6期12卷 979-997页

作者： Su, SYW Ranka, S He, X Univ Florida Dept Comp & Informat Sci & Engn Database Syst & Dev Ctr Gainesville FL 32611 USA Microsoft Corp Kirkland MA USA

In recent years, parallel processing and optimization algorithms for processing object-oriented databases have drawn a considerable amount of attention from the database research community. Two general types of algorithms have been introduced: hybrid-hash pointer-based algorithms and multiwavefront algorithms. In this work, we quantitatively analyze the two algorithms and develop analytical formulas to capture the main performance features of these two approaches. We study their performance in three application environments: One is characterized by large databases having many object classes, each of which contains a large number of instances;the second one is characterized by large databases having many object classes, each of which contains a relatively small number of instances;and the third one is by large databases having object classes of varying sizes. A horizontal data partitioning strategy, in which each object class is partitioned into horizontal segments stored across all processors, is used in the first environment. A class-per-node assignment strategy, in which instances of each object class are stored in a single processor, is used in the second environment. In the third environment, object classes are partitioned horizontally and assigned to a varying number of processors depending on their different sizes. Our analytical results show that the multiwavefront algorithm has three distinguishing features which contribute to its better performance: 1) two-phase processing strategy, 2) vertical partitioning of horizontal segments, and 3) dynamic determination of "collision point" in multiwavefront propagations which results in an optimized query execution plan. We show that if these features are adopted by a hybrid-hash, pointer-based algorithm, its performance will be comparable with that of the multiwavefront algorithm because the difference in CPU time between them is negligible. The assumed computing environment is a network of workstations having a sha

关键词： object-oriented databases parallel query processing algorithms performance analysis data partitioning strategies database benchmark

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Extending object-oriented databases for fuzzy information modeling

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INFORMATION SYSTEMS 2004年第5期29卷 421-435页

作者： Ma, ZM Zhang, WJ Ma, WY Wayne State Univ Dept Comp Sci Detroit MI 48202 USA Univ Saskatchewan Saskatoon SK S7N 5A9 Canada City Univ Hong Kong Hong Kong Hong Kong Peoples R China

In this paper, based on possibility distribution and the semantic measure of fuzzy data, we introduce an extended object-oriented database model to handle imperfect as well as complex objects in the real world. Some major notions in object-oriented databases such as objects, classes, objects-classes relationships, subclass/superclass, and multiple inheritances are extended under fuzzy information environment. A generic model for fuzzy object-oriented databases and some operations are hereby developed in the paper. (C) 2003 Elsevier Ltd. All rights reserved.

关键词： object-oriented databases fuzzy data semantic measure fuzzy object-oriented database model operations

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APPLICATION OF object-oriented databases TO GEOGRAPHIC INFORMATION-SYSTEMS

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INFORMATION AND SOFTWARE TECHNOLOGY 1991年第1期33卷 38-46页

作者： ROBERTS, SA GAHEGAN, MN HOGG, J HOYLE, B UNIV LEEDS SCH GEOGLEEDS LS2 9JTW YORKSHIREENGLAND UNIV LEEDS DEPT ELECT & ELECTR ENGNLEEDS LS2 9JTW YORKSHIREENGLAND

Geographic information systems (GISs) are required to support a wide range of applications, many of which involve vast quantities of data, typically requiring data structures and access paths not conveniently represented using traditional record-based data models. The object-oriented approach to database management has been developed principally to cater for engineering and scientific applications whose data are naturally viewed as a collection of objects. The question addressed by the paper is whether the object-oriented modelling semantics are suitable for geographic information and the spatial nature of relationships between objects. Three views of geographic information are presented and the object-oriented approach to data representation is examined in the light of each view. Examples of GIS functionality are based on a system developed by the authors.

关键词： GEOGRAPHIC INFORMATION SYSTEMS databases object-oriented object-oriented databases

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Graph-based parallel query processing and optimization strategies for object-oriented databases

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DISTRIBUTED AND PARALLEL databases 1998年第3期6卷 247-285页

作者： Su, SYW Huang, Y Akaboshi, N Univ Florida Database Syst Res & Dev Ctr Dept Comp & Informat Sci & Engn Dept Elect & Comp Engn Gainesville FL 32611 USA

Much work has been accomplished in the past on the subject of parallel query processing and optimization in parallel relational database systems;however, little work on the same subject has been done in parallel object-oriented database systems. Since the object-oriented view of a database and its processing are quite different from those of a relational system, it can be expected that techniques of parallel query processing and optimization for the latter can be different from the former. In this paper, we present a general framework for parallel object-oriented database systems and several implemented query processing and optimization strategies together with some performance evaluation results. In this work, multiwavefront algorithms are used in query processing to allow a higher degree of parallelism than the traditional tree-based query processing. Four optimization strategies, which are designed specifically for the multiwavefront algorithms and for the optimization of single as well as multiple queries, are introduced. The query processing algorithms and optimization strategies have been implemented on a parallel computer, nCUBE2;and the results of a performance evaluation are presented in this paper. The main emphases and the intended contributions of this paper are (1) data partitioning, query processing and optimization strategies suitable for parallel OODBMSs, (2) the implementation of the multiwavefront algorithms and optimization strategies, and (3) the performance evaluation results.

关键词： query processing and optimization object-oriented databases parallel algorithms data partitioning strategies

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INSIGHT INTO object-oriented databases

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INFORMATION AND SOFTWARE TECHNOLOGY 1990年第4期32卷 274-289页

作者： KHOSHAFIAN, S Ashton-Tate 2033 N Main Walnut Creek CA 94596 U.S.A.

object orientation offers a more direct and natural representation of real-world problems. object-oriented programming techniques enable the development of extensible and reusable modules. Combining the object-oriented contents of abstract data typing, inheritance, and object identity with database capabilities, such as persistence, transactions, concurrency, and query, results in powerful systems called object-oriented databases. These databases have become the dominant post-relational database management system and are a necessary evolutionary step toward the more powerful intelligent databases. Intelligent databases tightly join database and object-oriented technologies with artificial intelligence, information retrieval, and multimedia data manipulation techniques. Intelligent databases, along with intelligent database engines, are the most important component of future systems.

关键词： databases intelligent databases object-oriented object-oriented databases

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Supporting update propagation in object-oriented databases

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DATA & KNOWLEDGE ENGINEERING 1998年第1期26卷 99-115页

作者： Liu, CF Li, H Orlowska, ME Univ Queensland Cooperat Res Ctr Distributed Syst Technol Brisbane Qld 4072 Australia Univ Queensland Sch Informat Technol Brisbane Qld 4072 Australia

objects in a database are interrelated. When an update operation is applied to an object, it may also impact on its related objects, depending on the semantics of their relationships. Current OODBMSs provide no support for update propagation but hard-coding. In this paper, we study update propagation support for generic update operations in object-oriented databases. We take a declarative approach, specifying propagation policies for each identified reference attribute in classes of an object-oriented database schema. Propagation policies for generic update propagation are well defined. However, we also discover that potential conflicts among propagation policies may occur if the policies can be arbitrarily specified by a designer. Therefore, we promote the update propagation problem to a higher level, investigating possible dependencies between objects. As such, the designer only needs to specify the dependency property for each reference attribute. Propagation policies are predefined for each type of dependency. By introducing some restrictions on an object-oriented database schema, conflict-free propagation policies can be achieved. Implementation issues for update propagation support in object-oriented database systems are also addressed.

关键词： object-oriented databases update propagation propagation policy object dependency

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SYSTEM-GUIDED VIEW INTEGRATION FOR object-oriented databases

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IEEE TRANSACTIONS ON KNOWLEDGE AND DATA ENGINEERING 1992年第1期4卷 1-22页

作者： GOTTHARD, W LOCKEMANN, PC NEUFELD, A UNIV KARLSRUHE FAK INFORMATW-7500 KARLSRUHE 1GERMANY

View integration refers to the activity of merging the locally developed user-oriented views or schemas for a given environment of users and applications into a unique global conceptual schema. View integration is itself part of the larger activity of database design which has as its objective a database structure that satisfies to the best possible degree all data requirements of the potential users and all process requirements of the intended applications. The paper takes its cues from a survey article by Batini, Lenzerini, and Navathe who point out that despite ten or more years of intense research many issues still remain open. Chief among them are a low emphasis on full-scale automated systems, a lack of algorithmic specifications of the integration activities, inattention to the design of databases with new properties such as databases for computer-aided design, and insufficient experience with data models with a rich set of type and abstraction mechanisms. The paper takes all four into consideration by focusing on the realm of design databases for software engineering, by relying on a semantic model on the basis of structural object-orientation, by utilizing the expressiveness of the model to take first steps toward algorithmic solutions, and by demonstrating how corresponding tools could be embedded methodically within the view integration process and technically within a database design environment. The central idea is to compute so-called assumption predicates that express suggested similarities between structures in two schemas to be integrated, and then have a human integrator confirm or reject them. The basic method is exemplified for a data model that includes molecular aggregation, generalization, and versioning. Appropriate predicates, integration, and transformation primitives for automating part of the integration process are introduced. First experiences with an experimental prototype are related.

关键词： DATABASE DESIGN DATABASE DESIGN ENVIRONMENT DESIGN databases FOR SOFTWARE DEVELOPMENT ENTITY-RELATIONSHIP MODEL GLOBAL CONCEPTUAL SCHEMA object-oriented databases SEMANTIC MODEL SCHEMA INTEGRATION STRUCTURAL object-ORIENTATION VIEW INTEGRATION

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Optimal design of object-oriented databases in automatic information-control systems. II. Models and methods of design of optimal logical structures for object-oriented databases

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AUTOMATION AND REMOTE CONTROL 2005年第10期66卷 1690-1700页

作者： Kul'ba, VV Sirotyuk, VO Russian Acad Sci Trapeznikov Inst Control Sci Moscow Russia Eurasian Patent Agcy Moscow Russia

Part II is devoted to the formulation of the problem and models and methods of design of optimal logical structures for object-oriented databases used in designing automatic information control systems. The effectiveness criteria used for the problem design are defined by the minimal total time of utilization of databases and service of a given set of user inquires and transactions, minimal total time of implementation of a set of inquires and transactions over the database. Design problems are formulated as nonlinear integer programming problems and effective exact and heuristic algorithms are developed to solve them.

关键词： INFORMATION storage & retrieval systems ELECTRONIC information resources object-oriented databases databases object-oriented methods (Computer science) INTEGER programming NONLINEAR programming

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A MODEL FOR EVALUATION AND ADMINISTRATION OF SECURITY IN object-oriented databases

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IEEE TRANSACTIONS ON KNOWLEDGE AND DATA ENGINEERING 1994年第2期6卷 275-292页

作者： FERNANDEZ, EB GUDES, E SONG, HY BEN GURION UNIV NEGEV BEER SHEVAISRAEL INFORMIX SOFTWARE INC MENLO PKCA

The integration of object-oriented programming concepts with databases is one of the most significant advances in the evolution of database systems. Many aspects of such a combination have been studied, but there are few models to provide security for this richly structured information. We develop here an authorization model for object-oriented databases. This model consists of a set of policies, a structure for authorization rules, and algorithms to evaluate access requests against the authorization rules. User access policies are based on the concept of inherited authorization applied along the class structure hierarchy. We propose also a set of administrative policies that allow the control of user access and its decentralization. Finally, we study the effect of class structuring changes on authorization.

关键词： AUTHORIZATION MODELS DATABASE SECURITY object-oriented databases SECURITY ADMINISTRATION SECURITY OF object-oriented SYSTEMS

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A schema version model for complex objects in object-oriented databases

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JOURNAL OF SYSTEMS ARCHITECTURE 2006年第10期52卷 563-577页

作者： Lee, Sang-Won Ahn, Jung-Ho Kim, Hyoung-Joo Sungkyunkwan Univ Sch Informat & Commun Engn Suwon 440746 Gyeonggi South Korea IT4Web Seoul South Korea Seoul Natl Univ Seoul South Korea

In this paper, we propose a schema version model which allows to restructure complex object hierarchy in object-oriented databases. This model extends a schema version model, called RiBS, which is based on the concept of Rich Base Schema. In the RiBS model, each schema version is in the form of updatable class hierarchy view over one base schema, called the RiBS layer, which has richer schema information than any existing schema version in the database. In this paper, we introduce new operations for restructuring composite object hierarchy in schema versions, and explain their semantics. We also touch upon the ways to transform queries posed against a restructured composite object hierarchy into one against the base schema. In addition, we identify several types of conflicts during schema version merging which result from the restructuring operations, and provide a semi-automatic algorithm to resolve the conflicts. The originality of this paper lies in that (1) we introduce several new operations to restructure composite object hierarchy, and (2) this extended RiBS model operations raise the concept of data independence in OODBs upto the schema level. (c) 2006 Elsevier B.V. All rights reserved.

关键词： complex objects schema versions object-oriented databases schema version merging

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