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RELOOP, an algebra based query language for an object-oriented database system

Data & Knowledge Engineering 1990年第4期5卷 333-352页

作者： Cluet, Sophie Delobel, Claude Lecluse, Christophe Richard, Philippe Altaïr Altaïr is a consortium funded by IN2 (a subsidiary of the Siemens Group) INRIA (Institut National de Recherche en Informatique et Automatique) and LRI (the research lab of t 78153 Le Chesnay Cédex BP 105 France

In most object-oriented databases, as opposed to value-oriented databases, data are accessed by a programming language instead of a declarative query language. End users do not have a simple tool to perform their queries. This paper is concerned with the definition of an SQL-like query language on top of the O2 object-oriented database system. We study the influence of the object-oriented paradigm on a query language, describe our language through examples, define its semantics by means of an algebra and sketch the compilation of RELOOP in one of the languages supported by the O2 system.

关键词： Query language Algebra object-oriented database system SQL database programming language

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CRF:A Scheduling of Multi-Granularity Locks in object-oriented database systems

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Journal of systems Engineering and Electronics 1998年第4期9卷 51-57页

作者： Qin Xiao & Pang Liping(Department of Computer Science, Huazhong University of Science and Technology,Wuhan 430074, P. R. China) Department of Computer Science H azhong University of Science and Technology Wuhan 430074 P. R. China

This paper introduces a multi-granularity locking model (MGL) for concurrency control in object-oriented database system briefiy, and presents a MGL model formally. Four lockingscheduling algorithms for MGL are proposed in the paper. The ideas of single queue scheduling(SQS) and dual queue scheduling (DQS) are proposed and the algorithm and the performance evaluation for these two scheduling are presented in some paper. This paper describes a new idea of thescheduling for MGL, compatible requests first (CRF). Combining the new idea with SQS and DQS,we propose two new scheduling algorithms called CRFS and CRFD. After describing the simulationmodel, this paper illustrates the comparisons of the performance among these four algorithms. Asshown in the experiments, DQS has better performance than SQS, CRFD is better than DQS, CRFSperforms better than SQS, and CRFS is the best one of these four scheduling algorithms.

关键词： Lock scheduling Multi-granularity lock Concurrency control Compatible requestsfirst Single queue scheduling Dual queue scheduling object-oriented database system

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AN ACCESS-CONTROL MECHANISM FOR object-oriented database-systemS

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IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES 1993年第1期E76A卷 112-121页

作者： ARAKI, T CHIKARAISHI, T HARDJONO, T OHTA, T TERASHIMA, N

The security problems of object-oriented database system are investigated and security level assignment constraints and an access control mechanism based on the multilevel access control security policy are proposed. The proposed mechanism uses the Trusted Computing Base. A unique feature of the mechanism is that security levels are assigned not only to data items (objects), but also to methods and methods are not shown to the users whose security level is lower than that of the methods. And we distinguish between the security level of a variable in a class and that in an instance and distinguish between the level of an object when it is taken by itself and it is taken as a variable or an element of another complex object. All of this realizes the policy of multilevel access control.

关键词： INFORMATION SECURITY object-oriented database system MULTILEVEL ACCESS CONTROL SECURITY POLICY TRUSTED COMPUTING BASE

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Ownership as a conceptual modeling construct

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DATA & KNOWLEDGE ENGINEERING 2007年第2期62卷 248-273页

作者： Halper, Michael Liu, Li-Min Geller, James Perl, Yehoshua Kean Univ Dept Math & Comp Sci Union NJ 07083 USA Chung Yuan Christian Univ Dept Appl Math Chungli Taiwan New Jersey Inst Technol CS Dept Newark NJ 07102 USA

Ownership is a relationship that pervades many aspects of our lives, from the personal to the economic, and is particularly important in the realm of the emerging electronic economy. As it is understood on an intuitive level, ownership exhibits a great deal of complexity and carries a rich semantics with respect both to the owner and the possession. A formal model of an ownership relationship that inherently captures varied ownership semantics is presented. This ownership relationship expands the repertoire of available conceptual data modeling primitives. It is built up from a set of characteristic dimensions, namely, exclusiveness, dependency, documentation, transferability, and inheritance, each of which focuses on a specific aspect of ownership semantics. The data modeler has the ability to make a variety of choices along these five dimensions, and thus has access to a wide range of available ownership features in a declarative fashion. These choices ultimately impose various constraints (specified in OCL) on the states of data objects and their respective ownership activities, including transactions such as acquiring and relinquishing ownership. To complement the formal aspects of the ownership model and enhance its usability, we present a graphical ownership notation that augments the Unified Modeling Language (UML) class diagram formalism. An implementation of the ownership relationship in a commercial object-oriented database system is discussed. (c) 2006 Elsevier B.V. All rights reserved.

关键词： ownership relationship semantic relationship ownership semantics conceptual modeling object-oriented modeling object-oriented database system electronic commerce

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DICE: Declarative integrity constraint embedding into the object database standard ODMG-93

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DATA & KNOWLEDGE ENGINEERING 1997年第2期23卷 119-145页

作者： Fahrner, C Marx, T Philippi, S UNIV KOBLENZ DEPT COMP SCI KOBLENZ GERMANY UNIV MUNSTER INST WIRTSCHAFTSINFORMAT D-4400 MUNSTER GERMANY

In this paper we present a new approach for embedding integrity constraints into object-oriented database systems (OODBS), which can not be specified implicitly by structure or explicitly by keywords of the system. To take those integrity constraints into consideration they have to be integrated into the behavioral part of an object-oriented schema. This paper gives a survey of the existing proposals for this integration and presents a new one, DICE, to overcome the drawbacks of the reviewed solutions. As an example we describe the integration of DICE into object-oriented schema according to ODMG-93.

关键词： integrity constraint constraint checking object-oriented database system ODMG schema evolution

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A multi-level architecture for distributed object bases

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DATA & KNOWLEDGE ENGINEERING 2007年第1期60卷 150-184页

作者： Kirchberg, Markus Schewe, Klaus-Dieter Tretiakov, Alexei Wang, Baide Richard Massey Univ Informat Sci Res Ctr Palmerston North 5301 New Zealand

The work described in this article arises from two needs. First, there is still a need for providing more sophisticated database systems than just relational ones. Secondly, there is a growing need for distributed databases. These needs are addressed by fragmenting schemata of a generic object data model and providing an architecture for its implementation. Key features of the architecture are the use of abstract communicating agents to realise database transactions and queries, the use of a remote object call mechanism to enable remote agents to communicate with one another, and the use of multilevel transactions. Linguistic reflection is used to map database schemata to the level of the agents. Transparency for the users is achieved by using dialogue objects, which are extended views on the database. (c) 2005 Elsevier B.V. All rights reserved.

关键词： distributed database architecture object-oriented database system integration of programming and query language constructs multi-level transaction management persistent object store

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A survey of architectural features of contemporary object storage systems

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JOURNAL OF systemS ARCHITECTURE 1998年第5期45卷 363-386页

作者： Ahn, JH Lee, SW Song, HJ Kim, HJ Seoul Natl Univ Dept Comp Engn Gwanak Gu Seoul 151742 South Korea

In recent years, many object-oriented database systems have been developed and have become widely accepted in the DBMS commercial market. An efficient object manager, which is a middle layer on top of a storage system, is essential to ensure reasonable performance of object-oriented database systems, since a traditional record-based storage system is too simple to provide object abstraction. In this paper, we first explore the current state-of-the-art of object storage systems - object managers in combination with storage systems - by focusing on three main architectural issues: client-server architecture, object identifier representation, and the object access method. Then, we identify the dependencies between these factors and propose a general guideline for the design and implementation of an ideal object storage system that provides transparency, high performance, and flexibility. In addition, we briefly discuss transaction processing, object clustering, and object versioning that are closely related to improving the performance and the modeling power of object storage systems. (C) 1998 Elsevier Science B.V. All rights reserved.

关键词： object manager storage system object-oriented database system survey

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Representation of standard mechanical components in a STEP-based product data management system

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INTERNATIONAL JOURNAL OF COMPUTER APPLICATIONS IN TECHNOLOGY 1999年第1期12卷 16-26页

作者： Chao, PY Yeh, SC Natl Sun Yat Sen Univ Dept Mech Engn Kaohsiung 80424 Taiwan Natl Taiwan Univ Dept Mech Engn Taipei 10764 Taiwan

A product data management system, PDMS, stores and manages complete information about all its products and related activities. With proper management of such information, product development can be made easier and more efficient. Together with widespread computer network applications, PDMS enables an enterprise to exercise its business activities in a more efficient way. However, the standard representation of product data and their communication are two major obstacles to be overcome. In this paper, we present a set of procedures to represent a standard mechanical component and propose a method for the data management and its communication within the PDMS. The Standard for the Exchange of Product Model Data, STEP, is used for the data representation. The object database management system, ODBMS, is used for the data management because of the object-oriented nature developed by STEP. The open database connectivity, ODBC, server is also introduced for connecting different databases on the network. With the proposed procedure and architecture, we demonstrate the way to implement STEP and the way to merge the object-oriented modelled data in the PDMS. As STEP matures and computer networks Set faster and more popular, the networked PDMS will be a must for future enterprises.

关键词： BPR CALS concurrent engineering object-oriented database system PDMS STEP

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CLASSIFYING SCHEMATIC AND DATA HETEROGENEITY IN MULTIdatabase systemS

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COMPUTER 1991年第12期24卷 12-18页

作者： KIM, W SEO, JY MICROELECTR & COMP TECHNOL CORP OBJECT ORIENTED & DISTRIBUTED SYST LABAUSTINTX KOREA ADV INST SCI & TECHNOL DEPT COMP SCISEOUL 131SOUTH KOREA

A complete framework for enumerating and classifying the types of multidatabase system (MDBS) structural and representational discrepancies is developed. The framework is structured according to a relational database schema and is both practical and complete. It was used to build the UniSQL/M commercial multidatabase system. This MDBS was built over Structured-Query-Language-based relational database systems and a unified relational and object-oriented database system named UniSQL/X. However, the results are substantially applicable to heterogeneous database systems that use a nonrelational data model (for example, an object-oriented data model) as the common data model and allow the formulation of queries directly against the component database schemas

关键词： UniSQL/M data heterogeneity data integrity distributed databases multidatabase systems object-oriented database system object-oriented databases query languages relational database schema relational databases representational discrepancies

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STRAWMAN REFERENCE MODEL FOR object QUERY LANGUAGES

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COMPUTER STANDARDS & INTERFACES 1991年第1-3期13卷 185-199页

作者： BLAKELEY, JA THOMPSON, CW ALASHQUR, AM TEXAS INSTRUMENTS INC CTR COMP SCIINFORMAT TECHNOL LABZEITGEIST OPEN OODB PROJECTDALLASTX 75265

We begin by presenting a descriptive reference model that identifies the important features that need to exist in object query languages. This reference model can be used as a basis for comparing these languages and helps provide a foundation for future standardization efforts in this area. We then describe the main features of an object query language that is based on the type system of C++, which we refer to as OQL[C++]. A query module based on OQL[C++] is being developed as part of the Zeitgeist OODB project at Texas Instruments. OQL[C++] extends the C++ programming language by providing support for managing and associatively querying sets of objects in a C++ program. OQL[C++] queries are orthogonal to persistence in the sense that they can be issued against persistent as well as transient sets of objects. The proposed OQL[C++], provides an evolutionary path from the industry's standard query language SQL to an object query language. Using ideas similar to those presented in this paper, one can propose OQL[X] where X is either an object data model, or the type system of an object-oriented programming language such as CLOS or object Pascal.

关键词： QUERY LANGUAGES QUERY PROCESSING QUERY AND PROGRAMMING LANGUAGE INTEGRATION object-oriented database system

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