检索结果-内蒙古大学图书馆

The role of polymorphic reuse mechanisms in schema evolution in an object-oriented database

IEEE TRANSACTIONS ON KNOWLEDGE AND DATA ENGINEERING 1997年第1期9卷 50-67页

作者： Liu, L Zicari, R Hursch, W Lieberherr, KJ UNIV FRANKFURT FACHBEREICH INFORMATD-60325 FRANKFURTGERMANY NORTHEASTERN UNIV COLL COMP SCIBOSTONMA 02115 ZUEHLKE ENGN AG CH-8952 SCHLIERENSWITZERLAND

A seamless approach to the incremental design and reuse of object-oriented methods and query specifications is presented, We argue for avoiding or minimizing the effort required for manually reprogramming methods and queries due to schema modifications, and demonstrate how the role of polymorphic reuse mechanisms is exploited for enhancing the adaptiveness of database programs against schema evolution in an object-oriented database. The salient features of our approach are the use of propagation patterns and a mechanism for propagation pattern refinement Propagation patterns are employed as an interesting specification formalism for modeling operational requirements. They encourage the reuse of operational specifications against the structural modification of an object-oriented schema. Propagation pattern refinement is suited for the specification of reusable operational modules. It promotes the reusability of propagation patterns toward the operational requirement changes. This approach has a formal basis and emphasizes structural derivation of specifications. The main innovations are in raising the level of abstraction for behavioral schema design, and for making possible the derivation of operational semantics from structural specifications. As a result, both the modularity and reusability of object-oriented schemas are increased.

关键词： object-oriented database systems software reuse schema evolution adaptive software specification and development knowledge reasoning program adaptation

来源：评论

学校读者我要写书评

暂无评论

A database model for object dynamics

引用

VLDB Journal 1997年第2期6卷 73-96页

作者： Papazoglou, M.P. Krämer, B.J. Tilbury University INFOLAB 5000 LE Tilburg P.O. Box 90153 Netherlands FernUniversität Hagen D-58084 Hagen Germany

To effectively model complex applications in which constantly changing situations can be represented, a database system must be able to support the runtime specification of structural and behavioral nuances for objects on an individual or group basis. This paper introduces the role mechanism as an extension of object-oriented databases to support unanticipated behavioral oscillations for objects that may attain many types and share a single object identity. A role refers to the ability to represent object dynamics by seamlessly integrating idiosyncratic behavior, possibly in response to external events, with pre-existing object behavior specified at instance creation time. In this manner, the same object can simultaneously be an instance of different classes which symbolize the different roles that this object assumes. The role concept and its underlying linguistic scheme simplify the design requirements of complex applications that need to create and manipulate dynamic objects.

关键词： Dynamic class hierarchy Dynamic object re-classification object migration object role model object-oriented database systems

来源：评论

学校读者我要写书评

暂无评论

CACTIS - A SELF-ADAPTIVE, CONCURRENT IMPLEMENTATION OF AN object-oriented database-MANAGEMENT SYSTEM

引用

ACM TRANSACTIONS ON database systems 1989年第3期14卷 291-321页

作者： HUDSON, SE KING, R UNIV COLORADO DEPT COMP SCI BOULDER CO 80309 USA

Cactis is an object-oriented, multiuser DBMS developed at the University of Colorado. The system supports functionally-defined data and uses techniques based on attributed graphs to optimize the maintenance of functionally-defined data. The implementation is self-adaptive in that the physical organization and the update algorithms dynamically change in order to reduce disk access. The system is also concurrent. At any given time there are some number of computations that must be performed to bring the database up to date; these computations are scheduled independently and are performed when the expected cost to do so is minimal. The DBMS runs in the Unix/C Sun workstation environment. Cactis is designed to support applications that require rich data modeling capabilities and the ability to specify functionally-defined data, but that also demand good performance. Specifically, Cactis is intended for use in the support of such applications as VLSI and PCB design, and software environments.

关键词： Buffer management derived data object-oriented database systems self-adapted optimization

来源：评论

学校读者我要写书评

暂无评论

object-ORIENTATION AND THE SQL STANDARD

引用

COMPUTER STANDARDS & INTERFACES 1993年第2-3期15卷 287-300页

作者： KULKARNI, KG TANDEM COMP INC CUPERTINOCA 95014

The database language standard, SQL, adopted by both ANSI and ISO, is now well established as a language for developing database applications. The SQL standard has been evolving ever since its first adoption in 1986, with new revisions being announced every three years. The latest revision (SQL-92) has just been announced by both ANSI and ISO. Currently, work is underway on the next revision, SQL3, which is expected in 1995-96 timeframe. A major focus of SQL3 effort is to incorporate an object-oriented type system while maintaining strict upward compatibility with SQL-92. The type system of SQL3 is based on concepts such as abstract data types, object identity, polymorphism, subtypes-supertypes, parameterized types, dynamic binding, etc. In this paper, we report on the current status of SQL-3 type system.

关键词： ABSTRACT DATA TYPES ANSI C++ COBOL database LANGUAGES DYNAMIC BINDING ISO NESTED RELATIONS NON-1ST NORMAL FORM RELATIONS object IDENTITY MULTIPLE INHERITANCE MULTISETS object-oriented database systems OVERLOADING PARAMETERIZED TYPES POLYMORPHISM QUERY LANGUAGES RELATIONAL database systems SEMANTIC DATA MODELS SQL SQL-86 SQL-89 SQL-92 SQL3 TYPE TEMPLATES

来源：评论

学校读者我要写书评

暂无评论

SCHEMA EVOLUTION AND INTEGRATION

引用

DISTRIBUTED AND PARALLEL databaseS 1994年第1期2卷 101-126页

作者： CLAMEN, SM 1. School of Computer Science Carnegie Mellon University 15213 Pittsburgh PA

Providing support for schema evolution allows existing databases to be adjusted for varying roles over time. This paper reflects on existing evolution support schemes and introduces a more general and functional mechanism to support schema evolution and instance adaptation for centralized and distributed object-oriented database systems. Our evolution support scheme is distinguished from previous mechanisms in that it is primarily concerned with preserving existing database objects and maintaining compatibility for old applications, while permitting a wider range of evolution operations. It achieves this by supporting schema versioning, allowing multiple representations of instances to persist simultaneously, and providing for programmer specification of how to adapt existing instances. The mechanism is general enough to provide much of the support necessarily for heterogeneous schema integration, as well as incorporating much of the features of object migration and replication.

关键词： SCHEMA EVOLUTION HETEROGENEOUS SCHEMA INTEGRATION object-oriented database systems INSTANCE ADAPTATION

来源：评论

学校读者我要写书评

暂无评论

A set-oriented method definition language for object databases and its semantics

引用

CONCURRENCY AND COMPUTATION-PRACTICE & EXPERIENCE 2003年第14期15卷 1275-1335页

作者： Bertino, E Guerrini, G Merlo, I Univ Genoa Dipartinento Informat & Sci Informaz I-16146 Genoa Italy Univ Milan Dipartimento Sci Informaz I-20135 Milan Italy

In this paper we propose a set-oriented rule-based method definition language for object-oriented databases. Most existing object-oriented database systems exploit a general-purpose imperative object-oriented programming language as the method definition language. Because methods are written in a general-purpose imperative language, it is difficult to analyze their properties and to optimize them. Optimization is important when dealing with a large amount of objects as in databases. We therefore believe that the use of an ad hoc, set-oriented language can offer some advantages, at least at the specification level. In particular, such a language can offer an appropriate framework to reason about method properties. In this paper, besides defining a set-oriented rule-based language for method definition, we formally define its semantics, addressing the problems of inconsistency and non-determinism in set-oriented updates. Moreover, we characterize some relevant properties of methods, such as conflicts among method specifications in sibling classes and behavioral refinement in subclasses. Copyright (C) 2003 John Wiley Sons, Ltd.

关键词： object-oriented database systems rule-based languages database programming languages

来源：评论

学校读者我要写书评

暂无评论

Exploiting abstraction relationships' semantics for transaction synchronization in KBMSs

引用

DATA & KNOWLEDGE ENGINEERING 1997年第3期22卷 233-259页

作者： Rezende, FD Harder, T Department of Computer Science-University of Kaiserslautern P.O. Box 3049-67653 Kaiserslautern Germany

Currently, knowledge sharing is turning out to be a crucial area that needs to be supported by Knowledge Base Management systems (KBMSs). We propose an approach for transaction synchronization in KBMSs-LARS (Locks using Abstraction Relationships' Semantics). We show how we obtain serializability of transactions thereby providing different locking granules. The main benefit of our technique is the high degree of potential concurrency, which is obtained by means of a logical partitioning of the knowledge base (KB) grounded in the abstraction relationships, and the provision of many lock types to be used on the basis of each partition. In this way, we capture the abstraction relationships' semantics which are contained in a KB graph for transaction synchronization purposes and enable the exploitation of the inherent parallelism in a knowledge representation approach.

关键词： transaction synchronization concurrency control locking knowledge base management systems object-oriented database systems

来源：评论

学校读者我要写书评

暂无评论

object-oriented QUERY LANGUAGE FACILITATING CONSTRUCTION OF NEW objectS

引用

INFORMATION AND SOFTWARE TECHNOLOGY 1993年第9期35卷 519-529页

作者： ALHAJJ, R ARKUN, ME Bilkent University Faculty of Engineering Department of Computer Engineering and Information Sciences Bilkent 06533 Ankara-Turkey

In object-oriented database systems, messages can be used to manipulate the database;however, a query language is still a required component of any kind of database system. In the paper, we describe a query language for object-oriented databases where both objects as well as behaviour defined in them are handled. Not only existing objects are manipulated;the introduction of new relationships and new objects constructed out of existing ones is also facilitated. The operations supported in the described query language subsumes those of the relational algebra aiming at a more powerful query language than the relational algebra. Among the additional operators, there is an operator that handles the application of an aggregate function on objects in an operand while still having the result possessing the characteristics of an operand. The result of a query as well as the operands are considered to have a pair of sets, a set of objects and a set of message expressions;where a message expression is a sequence of messages. A message expression handles both stored and derived values and hence provides a full computational power without having an embedded query language with impedance mismatch. Therefore the closure property is maintained by having the result of a query possessing the characteristics of an operand. Furthermore, we define a set of objects and derive a set of message expressions for every class;hence any class can be an operand Moreover, the result of a query has the characteristics of a class and its superclass/subclass relationships with the operands are established to make it persistent.

关键词： database systems object-oriented database systems QUERY LANGUAGE object ALGEBRA MESSAGE EXPRESSION

来源：评论

学校读者我要写书评

暂无评论

SAMOS in hindsight: experiences in building an active object-oriented DBMS

引用

INFORMATION systems 2003年第5期28卷 369-392页

作者： Dittrich, KR Fritschi, H Gatziu, S Geppert, A Vaduva, A Univ Zurich Dept Informat Technol Database Technol Res Grp CH-8057 Zurich Switzerland

Active object-oriented database management systems incorporate, object-oriented database technology and active mechanisms such as event-condition-action rules (ECA-rules). SAMOS has been among the first representatives of this class of systems. During the development of SAMOS, numerous then open research questions have been addressed. In this paper, we present a "historical" perspective of the SAMOS project and report on lessons and experiences we have gained in the project. We identify requirements, present feasible solutions, and report on experiences we have drawn from this project. In particular, we describe the rule model of SAMOS;which represents a smooth integration of ECA-rules into an object-oriented data model. We also discuss the implementation and architecture of the SAMOS prototype on top of a passive object-oriented database management system (OODBMS). Furthermore, we report on performance and usability issues. In order to analyze performance, we have developed a benchmark;we discuss the experiences (and improvements) we have made by running the benchmark on SAMOS and by comparing the results to those obtained for other systems. Usability issues have been investigated with respect to tool support for designing SAMOS applications and analyzing rule systems. Finally, we discuss our experiences in implementing SAMOS and the conclusions we have drawn for the implementation of other types of event-based persistent systems as well as a development method for active systems in general. (C) 2002 Elsevier Science Ltd. All rights reserved.

关键词： active database systems object-oriented database systems ECA-rules

来源：评论

学校读者我要写书评

暂无评论

FORMAL SPECIFICATION OF A PERSISTENT object MANAGEMENT-SYSTEM

引用

INFORMATION AND SOFTWARE TECHNOLOGY 1993年第5期35卷 277-286页

作者： MURPHY, J GRIMSON, J UNIV DUBLIN TRINITY COLL DEPT COMP SCIDUBLIN 2IRELAND

The goal of the research on which the paper is based was to specify formally a persistent object management system and to implement a part of the specification in the form of a prototype. The prototype is called the persistent object storage manager (POSM). The prototype was implemented in C++ using the IBM OS/2 operating system. POSM is formally specified in the paper. The data model used in POSM is rigorously defined using the Z notation. The operations of POSM and its state space are also specified in Z notation. Example schemas for the operations of the node management component of the prototype are presented. Z notation is justified in the paper and the benefits of using Z in the research are discussed.

关键词： object MANAGEMENT object-oriented database systems FORMAL TECHNIQUES Z-NOTATION MATHEMATICS IN SOFTWARE DESIGN

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：