DODM：演绎型对象数据模型

演绎型对象数据库是演绎数据库和对象数据库结合的产物，它集成了演绎数据库的查询推理能力和对象数据库的强大建模能力。文中在已有的研究基础上较系统地研究演绎环境下对象数据模型，提出将类作为对象逻辑标识的集体和构造子；关系和集合为一类类构造子，体现了实体关系数据模型的思想；将型作为性质的集体，显式地区分类和型。引入型间偏相似关系来刻画继承语义，使得单继承、多继承和单调继承、非单调继承统一于型间偏相似关系，     

演绎对象库语言DOL的求值技术

ＤＯＬ语言是文中设计的一个演绎对象库语言，通过引入重载操作子，处理继承与重载的关系，文中讨论ＤＯＬ语言的基于程序重写的求值技术，研究表明，由于ＤＯＬ引入对象角色概念，程序重写技术的简单性。     

一个演绎对象数据库SD-DOOD的设计与实现

通过探寻面向对象数据库与知识库技术相结合的途径，研究演绎对象数据库系统实现的关键技术。以基于演绎数据库系统SD-DDBS，设计实现了一个演绎对象数据库系统原型SD-DOOD。系统支持类、类层次、对象、属性、方法、继承和封装等面向对象数据库系统的核心概念，支持演绎对象等演绎数据库的概念，提供了图形用户接口(GUI)，便于用户进行创建、查询等操作。     

产生证明责任验证Object—Z规格说明的行为子类型继承

Object-Z是形式规格说明语言Z的面向对象扩充,具有面向对象特点,适合描述大型面向对象软件规格说明.行为子类型继承是一种子类型继承,子类型对象拥有其超类对象的行为与属性,如果行为子类型对象替代其超类型对象时,运行时不会出错,经过验证过的形式规格说明不必再验证.本文对Object-Z定义了行为子类型继承,尤其我们系统地提出一个实现行为子类型继承和对规格说明产生相关证明责任的方法,其中这些证明责任可以判定形式规格说明是否按照其行为子类型方法进行开发的.最后,充分利用定理证明器Z/EVES来分析与验证所产生的证明责任.     

统计与科学数据库上的代数操作

针对统计与科学数据库的应用要求,本文以语义数据模型MICSUM2为基础,以C—关系、原子统计表和复合统计表为操作对象,定义了统计与科学数据库上的操作。这些操作构成了C—关系、原子统计表和统计表集合上的代数,简称MS代数。MS代数从两个方面扩展了关系代数,一是MS代数操作具有更丰富的语义和更广泛的操作对象;二是MS代数包括很多支持统计分析查询的新代数操作,MS代数是构造对用户友好的统计与科学数据库查询语言的理论基础。     

一种改进的基于角色的访问控制模型

本文提出一个改进的基于角色的访问控制模型(RBAC)。首先,把主体分为用户和角色,引入了角色层次及继承机制;其次,把客体分为对象和客体类,并在客体类上定义层次关系和继承机制;第三,提出操作类这一概念,在操作类上定义层次关系和继承机制;最后,引入了否定授权。通过这些改进,简化RBAC模型的授权管理。     

演绎对象数据库SD-DOOD中集合的应用和实现

基于复杂对象的逻辑推理一直是演绎对象数据库中的研究热点。论文叙述了集合在演绎对象数据库中的应用和实现技术,重点介绍了部分集在规则中的两个作用:列举集合中的所有元素和聚集集合中所有元素。同时讨论了完整集的交、并、划分和差等运算的实现思想。     

行为规范作为类型

在面向对象程序设计中，继承性是导致语义复杂性的因素之一．本文讨论了作为代码共享机制的继承和表示功能特殊化的子类型的共存及相互关系．采用了将行为规范视为类型的概念，即类型为命名操作的集合．并在此基础上给出了类型、类及子类型关系的形式描述．     

面向对象的数据库系统

本文描述作者对面向对象的数据库研究现状的一些看法。首先用这类系统的目标简要地定义这个领域,并把它与数据库的其它领域联系起来。描述面向对象系统的一些主要特征,包括封装,对象标识,类或型,继承,重载(overriding),以及迟后联编(Late binding),把这些特征统一地结合进数据库系统中是十分重要的。指出面向对象系统和面向对象数据库系统间的差别,以及相对于关系数据库系统来说,面向对象数据库系统的优缺点。最后列出某些研究的课题。     

对象语义理论和行为约束推理

本文基于时序模型观点建立对象语义理论，将对象定义为对象操作，对象属性和对象踪迹的集合，并由此给出对象继承，对象复合等概念的语义解释。对象类型是满足一组对象约束的同类对象的集合。有两类不同的对象约束：状态约束表示对象属性之间的关联，而时序约束则表示事件操作之间的时序关联。文章最后用例子表明对象约束推理应用。     

事务逻辑对象库语言

对象封装了结构和行为.对象数据库为大规模复杂应用提供良好的建模方法和实现手段.对象与逻辑结合导致目前对演绎对象库的研究.然而,这些研究基本上针对对象的结构描述,而很少涉及到对象的动态行为的描述.该文重点研究对象的动态行为,分析对象特征：继承和重载对事务语义的影响,并设计了一个事务对象库语言TOL(transaction object base language).首先分析TOL中的基本更新活动的特征,然后研究其事务的模型论语义.TOL模型论语义基于通路结构.     

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.     

Design and Implementation of the ROL Deductive Object-Oriented Database System

ROL is a deductive object-oriented database system that has been implemented at the University of Regina. It provides a uniform rule-based declarative language for defining, manipulating and querying databases, which integrates important features of both deductive databases and object-oriented 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. This paper describes its design and implementation. An important novel feature of the implementation is that it combines top-down and bottom-up evaluation strategies and automatically selects a strategy based on the nature of the query and data in the database.     

The Implementation of a Deductive Query Language Over an OODB

The ROCK and ROLL database system cleanly integrates deductive and object-oriented capabilities by defining an imperative programming language, ROCK, and a declarative, deductive language, ROLL, over a common object-oriented (OO) data model. Existing techniques for evaluation and optimization of deductive languages fail to address key requirements imposed by ROLL such as: strict typing; placement of deductive methods (predicates) within classes; encapsulation; overriding and late binding. This paper describes the task of implementing an evaluator and optimizer for ROLL, explaining how existing implementation techniques for deductive languages were adapted to meet these requirements and extended to support novel types of optimization.     

DOOL程序语义等价转换为Datalog 程序的转换规则

演绎对象数据库(DOOD)是演绎数据库与面向对象数据库两者优点相结合的产物。笔者设计实现了一个演绎对象数据库系统原型SD-DOOD,它是基于演绎数据库系统SD-DDBS的。然而,它使用的是演绎对象库语言DOOL,而演绎数据库语言是基于Datalog的,因此该文提出了应用一些转换规则来将DOOL程序转换为Datalog,通过规则转换,能求出DOOL程序的最小不动点(即程序值),从而使得系统的查询操作全都由SD-DDBS最终得出结果。文中详细介绍了转换规则的具体内容。     

Trigger inheritance and overriding in an active object databasesystem

An active database is a database in which some operations are automatically executed when specified events happen and particular conditions are met. Several systems supporting active rules in an object oriented data model have been proposed. However, several issues related to the integration of triggers with object oriented modeling concepts have not been satisfactorily addressed. We discuss issues related to trigger inheritance and refinement in the context of the Chimera active object oriented data model. In particular, we introduce a semantics for an active object language that takes into account trigger inheritance and supports trigger overriding. Moreover, we state conditions on trigger overriding ensuring that trigger semantics is preserved in subclasses     

ON TEMPORAL DEDUCTIVE DATABASES

This article introduces a temporal deductive database system featuring a logic programming language and an algebraic front-end. The language, called Temporal DATALOG, is an extension of DATALOG based on a linear-time temporal logic in which the flow of time is modeled by the set of natural numbers. Programs of Temporal DATALOG are considered as temporal deductive databases, specifying temporal relationships among data and providing base relations to the algebraic front-end. The minimum model of a given Temporal DATALOG program is regarded as the temporal database the program models intensionally. The algebraic front-end, called TRA, is a point-wise extension of the relational algebra upon the set of natural numbers. When needed during the evaluation of TRA expressions, slices of temporal relations over intervals can be retrieved from a given temporal deductive database by bottom-up evaluation strategies.
A modular extension of Temporal DATALOG is also proposed, through which temporal relations created during the evaluation of TRA expressions may be fed back to the deductive part for further manipulation. Modules therefore enable the algebra to have full access to the deductive capabilities of Temporal DATALOG and to extend it with nonstandard algebraic operators. This article also shows that the temporal operators of TRA can be simulated in Temporal DATALOG by program clauses.