Introduction to object-oriented databases

The object-oriented approach is being used in several areas of computing, including programming, databases, computer-aided design, and office information systems. The paper is a tutorial introduction to object-oriented databases, which is a new application in this field, although object-oriented programming has been under development since the late 1960s. The paper describes the background to object-oriented databases and outlines the rationale for this approach. It concludes with a possible application, in this case a cartographic database, explaining why the object-oriented approach is more appropriate to this application than traditional database approaches, such as the relational approach.     

面向对象XML的对象迁移方法研究

针对面向对象的XML数据的对象迁移问题,提出基于集中式和分布式两种存储模式下的对象迁移方法,解决了对象标识符模糊性问题。集中式存储模式对象的OID是唯一的,但是在集中式存储模式中更新已存在的对迁移对象的引用代价很大;分布式存储模式对象的OID是多重的,但对象迁移的代价相对较小。     

Approaches to deductive object-oriented databases

The paper is concerned with the problem of combining deductive and object-oriented features to produce a deductive object-oriented database system which is comparable to those currently available under the relational view of data modelling not only in its functionality but also in the techniques employed in its construction and use. Under this assumption, the kinds of issues that have to be tackled for a similar research strategy to produce comparable results are highlighted. The authors motivate their terms of comparison, characterize three broad approaches to deductive object-oriented databases and introduce the notion of language convergence to help in the characterization of some shortcomings that have been perceived in them. Three proposals that have come to light in the past three years are looked into in some detail, in so far as they exemplify some of the positions in the space of choices defined. The main contribution of the paper is towards a characterization of the language convergence property of deductive database languages which has a key role in addressing critiques of the deductive and object-oriented database research enterprise. A basic familiarity with notions from deductive databases and from object-oriented databases is assumed.     

关系数据模型与面向对象数据模型的关系探讨

面向对象数据模型的应用打破了油田单一关系数据库体系架构。如何在面向对象数据模型和关系数据模型并存条件下构建和优化协调统一的数据库体系架构,是油田数据库建设的重要技术方向之一。本文从油田数据库应用的角度概要对比了关系数据模型和面向对象数据模型的特点,对关系数据模型和面向对象数据模型共存条件下建立油田数据库体系架构的可能性进行了探讨。     

An Overview of the Rule-Based Object Language

This paper presents an overview of a novel strongly typed deductive object database language, called Rule-based Object Language, which is being developed at the University of Regina. Rule-based Object Language is a uniform language for defining, querying, and manipulating a database, which integrates important features of deductive databases and object databases. It supports object identity, complex objects, classes, class hierarchies, multiple inheritance with overriding and blocking, and schema definition. It also supports structured values such as functor objects and sets, treating them as first class citizens and providing powerful mechanisms for representing both partial and complete information about sets. Important integrity constraints such as domain, referential, functional dependency, multi-valued dependency, and cardinality are built-in in a uniform framework. Rule-based Object Language directly supports non-first normal form relations and is an extension of the pure valued-oriented deductive languages such as Datalog and LDL (without grouping) and subsumes them as special cases. It supports schema, object, fact and rule queries in a uniform framework. It also supports schema, fact and rule updates.     

面向对象数字地质图数据模型的研究

本文结合国内外的研究成果,吸收面向对象的思想和方法,利用统一建模语言UML,完成了面向对象数字地质图数据模型的建立。从制图学的角度出发,设计了数字地质图数据的概念模型、逻辑模型,定义了构成数字地质图各要素间的逻辑关系,并简要叙述了物理模型的实现平台和建立过程。面向对象的数字地质图数据模型打破了关系模型范式的限制,更加合理地将空间数据和属性数据有效地融合在一起,为数字地质图的高效存储、管理、分析、应用、可视化表达提供一种科学、合理、可靠、可操作性强的机制和模式,作为一种尝试和探索,具体的设计和实施还有待于进一步研究。     

基于面向对象技术的数据仓库设计与实现

介绍了数据仓库技术的概念与内容,研究了运用面向对象技术建立数据仓库系统的关键技术。以某化工企业决策支持系统为背景,给出了基于面向对象技术的数据仓库的设计方案,并对其逻辑设计,前端展现程序设计进行了探讨。     

Modeling and Management of Fuzzy Information in Multimedia Database Applications

In this paper, we firstly present a conceptual data model for multimedia database applications based on ExIFO₂ model. The ExIFO₂ data model is chosen as the conceptual model since it handles complex objects along with their uncertain and imprecise properties. We enhanced this conceptual model in order to meet the multimedia data requirements. In addition to uncertain and imprecise information, we present a way of handling relationships among objects of multimedia database applications. Events that might be extracted from video or audio are also considered in this study. Secondly, the conceptual model is mapped to a logical model, which the fuzzy object-oriented data (FOOD) model is chosen, for storing and manipulating the multimedia objects. This mapping is done in a way that it preserves most of the information represented at the conceptual level. Finally, in this study videos of football (soccer) games is selected as the multimedia database application to show how we handle crisp and fuzzy querying and retrieval of fuzzy and crisp data from the database. A program has been developed to draw ExIFO₂ schemas and to map the schema to FOOD code automatically.     

模糊面向对象数据库中的模糊对象匹配

对象匹配的目标在于区分对象,用以识别多个对象是否代表相同的现实世界实体,其在数据集成和数据清洗等方面发挥着至关重要的作用.为了满足同时处理复杂对象、复杂对象关系以及不确定数据的需求,模糊面向对象数据库的研究近年来受到了研究者的关注.本文识别出模糊面向对象数据库中模糊对象的三种情况:两个模糊对象属于同一个类;两个模糊对象分属于具有子类/超类关系的两个类;两个模糊对象分属于两个完全不同的类.针对不同的模糊对象情况,基于可能性理论和模糊数据的语义测度,给出了计算两个模糊对象等价度和必要度的方法.     

Supporting production rules using ECA rules in an object-oriented context

This paper presents an approach to implementing production rules for object-oriented databases (OODBs). The approach builds upon earlier work on production rule algorithms for relational databases, and exploits fundamental differences in the structuring mechanisms employed by OODBs. An implementation is described whereby the production rules are mapped onto eventcondition action rules for execution. It is shown how the resulting implementation has minimal space overheads, and a time performance close to that of the widely used TREAT algorithm which uses significantly more space.     

面向对象的数据库设计中的应用

主要探索一种将面向对象分析应用到数据库系统设计的方法，利用此方法实现一个管理系统，这一方法是把类的整体与部分关系，一般与特殊关系和实例连接应用到数据库设计中，此方法利用了数据库的基本且简单的功能，因而适应性强，可靠性高。     

View specification and manipulation for a semantic data model

Semantic data models are increasing in popularity and use, but they are also becoming increasingly complex and difficult to manage. In this paper we extend the definition of a semantic data model to give users the power to specify and manipulate views. Our model supports both high-level object-class views and high-level relationship-set views. To define these views, we extend the traditional method of view definition (through query formulation) to also include view definition by a dominant object class, by an independent object class, and by a relational object class. A set of operators to specify and manipulate views is also defined. These operators allow a user to create and destroy views, implode and explode views, hide and expose semantic-model elements. We also provide algorithms to extract an instance graph for a high-level object in a semantic-model view and to transform a semantic-model view hierarchy into an equivalent atomic model. Implications and applications of views in our model are also discussed.     

基于IDEF1x的面向对象XML建模

为了在IDEF1x数据库模型和面向对象模型的XML文档之间共享统一的模型,提出并实现了一种基于IDEF1x模型的面向对象XML建模方法.根据IDEF1x方法建立数据库模型,得到该模型的XML文档,然后对XML文档进行解析和重新组合,转换成为面向对象模型,并且生成该模型的XML Schema文档.     

从面向功能到面向对象模型的转换策略研究

有不少软件公司在软件开发过程中同时使用了面向功能的和面向对象的技术,例如在开发某一系统时,在采用了面向功能的分析模式后又使用了面向对象的设计方法,因此找到一种方法来实现从一种模式向另一种模式的转换是相当有必要的.提出了一种灵活可行的从面向功能的分析模型到面向对象的设计模型的转换策略.     

Formalization of object-oriented database model with rules

The paper investigates knowledge representation in an object-oriented database management system first within the data model with rules and second in the computational model by using logic. Issues of structure, integrity, and retrieval are focused on. The proposed system provides object-oriented concepts for describing complex structured data, rules for expressing object-dependent constraints and object associations, and, finally, logic for inference and retrieval.     

Managing Information in a Co-operative Object Database System

The paper describes a software infrastructure that was built to manage information in a co-operative environment for the design of control systems. The architecture of the environment, the organization of the design database and a suite of information management tools are presented. The paper suggests that the distributed client–server architecture and object database technology meet the requirements of managing information in the environment. The following issues related to information management are examined in more detail: support for version control, maintenance of information integrity by means of object access control and consistency control, support for user co-operation based on object sharing and change notification, graphical user interfaces, and design tool interfaces. Problems encountered during the implementation of the environment using a commercial object database management system are also discussed.     

面向对象的对象建模技术及其应用研究

面向对象的软件开发方法的关键是对问题域的理解,对象建模技术（OMT）在面向对象的软件系统建模中具有较好的性能。本文研究了OMT的三种模型、对象之间关系的描述策略,以OMT方法为指导设计了一个自动售货机模型,并进行了原型实现。研究结果表明：基于对象建模技术的系统构建过程更直观、开发人员易沟通,各开发阶段使用统一的概念模型,减少了相互转换过程中的错误和冗余。     

Autonomous objects: A natural model for complex applications

Object-oriented database systems are emerging as the next generation DBMSs for advanced applications, e.g., VLSI design, mechanical CAD/CAM, software engineering, etc. However, a close analysis indicates that the requirements imposed by these application domains cannot be met by an object-oriented model that relies purely onpassive objects. In this work we go beyond the conventionalsingle-thread-of-control paradigm of passive object models and propose a model ofactive objects which can autonomously initiate responses to environmental changes.Autonomous objects cooperate with each other by synchronous orasynchronous message passing—giving rise to themultiple-thread-of-control in such an environment. It is shown howevents—to which active objects react—can be incorporated into this model. We propose a nondeterministic computational model for the individual active objects that allows the autonomous reaction upon events. We show that this very sparse extension to an object-oriented model gives rise to several high-level features which can be controlled by events. The object-oriented paradigm allows one to isolate the rules according to which events are being raised. This leads to a potentially rather efficient execution model compared to existing relational concepts, which are typically globally-defined event trigger mechanisms.     

支持对象间关系的程序设计语言研究

在论述了面向对象技术中对象间的关系作为第一级建模概念的重要性之后,该文设计并实现了显式支持对象间关系的RCPP(relational C++)语言.它提供了显式描述对象间关系特性和语义的机制,利用关系来动态地控制对象行为的作用和传播.它的运行是通过一个转换器把RCPP代码翻译成C++代码,再经C++环境编译后,形成可执行程序而实现的.文章对RCPP语言的模型、语言提供的服务以及具体系统的描述和实现作了深入阐述.     

Object Identity in Database Systems

The concept of object identity and implementation of object identity in some systems have been explained in literature.Based on an analysis on the idea of data scheme in ANSI/X3/SPARC,this paper presents the concept of full-identity,which includes entity identity,conceptual object identity,and internal object identity,In addition,the equality of objects,which is richer and more practical,is discussed based on the full identity of objects.Therefore,the semantics and constructions of the identity for the complex objects are fully observed,and some appliactions in object management,version management,and user interface are found.Also,it could support the combination of O-O model with V-O model.