This paper describes an evolution framework supporting customization of the schema evolution and instance adaptation approaches in an object database management system. The framework is implemented as an integral part...
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Efficient execution of an object method has a great impact on a query response time. Optimising access to data returned by methods is difficult as methods are written in a high-level programming language and their cod...
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ISBN:
(纸本)3540408606
Efficient execution of an object method has a great impact on a query response time. Optimising access to data returned by methods is difficult as methods are written in a high-level programming language and their code is usually hidden to a query optimiser in order to preserve encapsulation. Moreover, estimating the cost of executing a method is another serious problem. In this paper we propose a framework for the materialisation of method results in objectdatabases. In our approach, the materialisation of method m results also in the materialisation of intermediate results of methods called from m. We call this technique hierarchical materialisation. The hierarchical materialisation technique was implemented and evaluated in a prototype based on the Fastobjects t7 object-oriented database.
This paper presents a language designed for the description of both temporal schema versioning and schema modification in object-oriented databases. The language supports temporal and versions features in both schemat...
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In this paper, we focus on conceptual data modeling and logical database modeling of fuzzy information. The IFO data model is extended with fuzzy set theory to cope with imperfect as well as with complex objects in th...
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In this paper, we focus on conceptual data modeling and logical database modeling of fuzzy information. The IFO data model is extended with fuzzy set theory to cope with imperfect as well as with complex objects in the real world at a conceptual level. Concerning the logical database modeling of fuzzy information, we focus on the object-oriented database model. Some major notions in the object-oriented databases such as objects, classes, objects-classes relationships, supertype/subtype, and multiple inheritances are extended under fuzzy information environment, and a generic model for fuzzy object-oriented databases is developed. In particular, we develop the formal approach to mapping a fuzzy 1170 (IF2O) model to a fuzzy object-oriented database schema. Therefore, one can conduct the conceptual design of a database model with fuzzy information and then transform it into the logical database model.
Even though object-oriented development was introduced in the late 1960s(beginning with the Simula programming language), OO development has not yet lived up to itspromises. A major stumbling block to reaping the prom...
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Even though object-oriented development was introduced in the late 1960s(beginning with the Simula programming language), OO development has not yet lived up to itspromises. A major stumbling block to reaping the promised benefits is learning the OO approach (see[6]). One reason that learning OO is so difficult may be that we do not yet thoroughly understandthe fundamental concepts that define the OO approach. When reviewing the body of work on OOdevelopment, most authors simply suggest a set of concepts that characterize OO, and move on withtheir research or discussion. Thus, they are either taking for granted that the concepts are knownor implicitly acknowledging that a universal set of concepts does not exist. Several authors,asserting there is no clear definition of the essence of OO, have called for the development of aconsensus. While a few have tried to develop such a consensus, to date a thorough review of theliterature and identification of the fundamental concepts of the OO approach has been lacking. Thegoal of this article is twofold: to identify and describe the fundamental concepts, or quarks, ofobject-oriented development, and identify how these concepts fit together into a coherent scheme.
The two main techniques of improving I/O performance of objectoriented Database Management Systems (OODBMS) are clustering and buffer replacement. Clustering is the placement of objects accessed near to each other in...
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The two main techniques of improving I/O performance of objectoriented Database Management Systems (OODBMS) are clustering and buffer replacement. Clustering is the placement of objects accessed near to each other in time into the same page. Buffer replacement involves the selection of a page to be evicted, when the buffer is full. The page evicted ideally should be the page needed least in the future. These two techniques both influence the likelihood of a requested object being memory resident. We believe an effective way of reducing disk I/O is to take advantage of the synergy that exists between clustering and buffer replacement. Hence, we design a framework, whereby clustering algorithms incorporating buffer replacement cache behaviour can be conveniently employed for enhancing the I/O performance of OODBMS. We call this new type of clustering algorithm, Cache Conscious Clustering (C3). In this paper, we present the C3 framework, and a C3 algorithm that we have developed, namely C3-GP. We have tested C3-GP against three well known clustering algorithms. The results show that C3-GP out performs them by up to 40% when using popular buffer replacement algorithms such as LRU and CLOCK. C3-GP offers the same performance as the best existing clustering algorithm when the buffer size compared to the database size is very small. (C) 2006 Elsevier B.V. All rights reserved.
The article reports on the importance of object-oriented (OO) approach in achieving a high degree of reuse with the development of countless highly accessible libraries and frameworks and their concomitant availabilit...
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The article reports on the importance of object-oriented (OO) approach in achieving a high degree of reuse with the development of countless highly accessible libraries and frameworks and their concomitant availability. Examples of this reuse include graphical user-interface libraries such as Microsoft Foundation Classes and Java Swing, as well as container and algorithm classes such as the C standard library. However, reusing object libraries and frameworks requires skill in OO programming and an underlying knowledge of the classes, as well as the services that they provide.
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],...
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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.
In this paper, we propose a solution for the query translation between object-oriented and relational databases. The translation was accomplished through a schema transformer and a query translator. The mapping rules ...
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In this paper, we propose a solution for the query translation between object-oriented and relational databases. The translation was accomplished through a schema transformer and a query translator. The mapping rules defined within the schema transformer describe the transformation between an object-oriented schema and a relation schema. Then the query translator provides users a relational view of an object-oriented database, and vice-versa. In this work, we used Entity/Relationship model as a tool to describe the real world since Entity/Relationship model can be easily mapped to an object-oriented or relational schema according to the underlying DBMS. Finally, we implemented the query translation between OOSQL for WOO, an object-oriented database system developed at the Institute for the Information Industry, and SQL for the Microsoft FoxPro relational database system.
The paper proposes a three-dimensional matrix model for representation of entities, attributes, relationships and attribute values of databases in order to access them through menus with predefined fields when posing ...
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ISBN:
(纸本)9789549641332
The paper proposes a three-dimensional matrix model for representation of entities, attributes, relationships and attribute values of databases in order to access them through menus with predefined fields when posing *** is discussed that the databases, described by the proposed model can be synonymously defined by the structures, used in the modern object-oriented programming languages, such as classes, objects and dynamical arrays.
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