Object-oriented Database Language Research Articles

Designing workshop management system supporting decision making with OODB

In this study, a workshop production management system supporting decision making is designed for use in small and medium-sized machine workshops. Small and medium sized companies’ quality, price, and delivery time issues are in a tough competitive environment. Especially such as the orders which cannot be delivered to customers in time, disruptions in production schedules and low production performance seem to be the major problems facing in this type of sector. Through this research it is aimed to design software to keep all the needed information in a suitable database and give the customers fast and accurate information. In order to support future implementation of decision support system, the software is designed such that it will enable the user to easily analyze its production parameters such as efficiency, cost deviation of production from planned cost, cost estimation of new production, etc. Due to the natural structure of this project Object Oriented database is chosen for implementation. These databases can be constructed through object-oriented language and in the scope of this work .NET based db4o is used. For software development, Unified Modelling Language (UML) is used since by using UML the database system is well defined, visualized, generated and specified considering complete project. The user interfaces are designed by using ASP.NET for easy access of the user location independently. It is seen that without using so much coding load, an effective object-oriented database can be designed. It is possible to use the same language for both application and object-oriented databases in contrast to relational databases. The designed database can be used in different machine workshops with small modifications depending on the specifications of workshops.

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

AbstractIn 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 © 2003 John Wiley & Sons, Ltd.

A deductive probabilistic and fuzzy object-oriented database language

We introduce a deductive probabilistic and fuzzy object-oriented model where a class property (i.e., an attribute or a method) can contain fuzzy set values, and uncertain class membership and property applicability are measured by lower and upper bounds on probability. Each uncertainly applicable property is interpreted as a default probabilistic logic rule, which is defeasible, and probabilistic default reasoning on fuzzy events is proposed for uncertain property inheritance and class recognition. This provides a formal basis for the design and implementation of FRIL++, the object-oriented extension of FRIL, a logic programming language dealing with both probability and fuzziness. The basic features of FRIL++ and its application as a programming language for deductive probabilistic and fuzzy object-oriented databases are presented.

Federated Process Framework in a Virtual Enterprise Using an Object-Oriented Database and Extensible Markup Language

Process information sharing is a beneficial tool through which participating organizations in a virtual enterprise can improve their customer services and business performance. However, autonomy and agility of the organizations have placed limitations in the development of process information sharing, which the previous research has not satisfactorily addressed. This paper proposes a federated process framework and its system architecture that provide a conceptual design for effective implementation of process information sharing supporting the autonomy and agility of the organizations. First, in terms of autonomy, the federated process framework supports a flexible sharing policy to control the amount of shared data so that the framework can be applied to a wide variety of practical situations from loosely-coupled cases to tightly-coupled cases. Second, in terms of agility, the system architecture based on the federated process framework supports the entire life cycle of process information sharing by allowing sufficient adaptability to the changes of business environments. We develop the framework using an object-oriented database and Extensible Markup Language to accommodate all the constructs and their interactions within object-oriented message exchange model.

연역 객체 지향 데이터베이스 언어 구현을 통한 XML 데이터 처리에 관한 연구

본 논문에서는 XML 데이터와 같은 비구조적인 데이터 처리와 추론을 필요로 하는 의미 웹(semantic web) 구축에 유리한 연역 객체 지향 데이터베이스(Deductive and Object-oriented Database) 언어구현을 통해 XML 데이터 처리에 대해 알아본다. 대량 문서 관리와 데이터 교환에 가장 유용한 마크업 언어로 알려진 XML을 이용하여 XML 데이터 모델을 연역객체지향 데이터베이스 모델로 바꾸는 방법에 대해 알아본 다음 이 연역객체 지향 데이터베이스를 다시 Connection Graph로 바꾸고 Connection Graph Resolution을 이용하여 어떻게 질의에 답할 수 있는지를 기술한다. 또한 데이터베이스 내의 계층 지식을 이용하여 효율적이면서도 같은 답을 주는 질의로 바꾸는 방법을 제시하고 이 방법이 효율적이며 논리적으로 타당하다는 점을 증명한다. With the advent of XML and database languages armed with the object-oriented concept and deductive logic, the problem of efficient query processing for them has become a major issue. We describe a way of processing semi-structured XML data through an implementation of a Deductive and Object-oriented Database (DOODB) language with the explanation of query processing. We have shown how to convert an XML data model to a DOODB data model. We have then presented an efficient query processing method based on Connection Graph Resolution. We also present a knowledge-based query processing method that uses the homomorphism of objects in the database and the associative rule of substitutions.

A logical foundation for deductive object-oriented databases

Over the past decade, a large number of deductive object-oriented database languages have been proposed. The earliest of these languages had few object-oriented features, and more and more features have systematically been incorporated in successive languages. However, a language with a clean logical semantics that naturally accounts for all the key object-oriented features, is still missing from the literature. This article takes us another step towards solving this problem. Two features that are currently missing are the encapsulation of rule-based methods in classes, and nonmonotonic structural and behavioral inheritance with overriding, conflict resolution and blocking. This article introduces the syntax of a language with these features. The language is restricted in the sense that we have omitted other object-oriented and deductive features that are now well understood, in order to make our contribution clearer. It then defines a class of databases, called well-defined databases , that have an intuitive meaning and develops a direct logical semantics for this class of databases. The semantics is based on the well-founded semantics from logic programming. The work presented in this article establishes a firm logical foundation for deductive object-oriented databases.

A semantic object-oriented data access system

Lack of support for Entity-Relationship (E-R) semantics and the disconnect between object-oriented programming languages (OOPLs) and database languages remain key roadblocks to the effective use of object-orientation in information systems development. We present SOODAS, a Semantic Object-Oriented Data Access System that defines and manages the meta-data necessary to support E-R semantics and set level querying and provides related interface generation tools. SOODAS consists of five meta-classes. DomainObject and Relationship provide the capabilities needed to define and manage entities, attributes, relationships, external identifiers, and constraints. Together with the meta-class QueryNode, DomainObject provides an object-oriented, multi-entity querying capability. Queries can be arbitrarily complex and can include cycles and transitive closure. Persistence is provided by the meta-class, PermanentObject, of which DomainObject and Relationship are subclasses. The meta-class, DomainObjectInterface uses the meta-data in DomainObject and Relationship to generate a standard, re-usable interface for displaying and maintaining instances of any entity. Since SOODAS is implemented entirely in Smalltalk, it can be seamlessly integrated with any Smalltalk application.

Unifying Class-Based Representation Formalisms

The notion of class is ubiquitous in computer science and is central in many formalisms for the representation of structured knowledge used both in knowledge representation and in databases. In this paper we study the basic issues underlying such representation formalisms and single out both their common characteristics and their distinguishing features. Such investigation leads us to propose a unifying framework in which we are able to capture the fundamental aspects of several representation languages used in different contexts. The proposed formalism is expressed in the style of description logics, which have been introduced in knowledge representation as a means to provide a semantically well-founded basis for the structural aspects of knowledge representation systems. The description logic considered in this paper is a subset of first order logic with nice computational characteristics. It is quite expressive and features a novel combination of constructs that has not been studied before. The distinguishing constructs are number restrictions, which generalize existence and functional dependencies, inverse roles, which allow one to refer to the inverse of a relationship, and possibly cyclic assertions, which are necessary for capturing real world domains. We are able to show that it is precisely such combination of constructs that makes our logic powerful enough to model the essential set of features for defining class structures that are common to frame systems, object-oriented database languages, and semantic data models. As a consequence of the established correspondences, several significant extensions of each of the above formalisms become available. The high expressiveness of the logic we propose and the need for capturing the reasoning in different contexts forces us to distinguish between unrestricted and finite model reasoning. A notable feature of our proposal is that reasoning in both cases is decidable. We argue that, by virtue of the high expressive power and of the associated reasoning capabilities on both unrestricted and finite models, our logic provides a common core for class-based representation formalisms.

Active Rule Termination Analysis: An Implementation and Evaluation of the Refined Triggering Graph Method

This paper describes the implementation of the Refined Triggering Graph (RTG) method for active rule termination analysis and provides an evaluation of the approach based on the application of the method to a sample active application. The RTG method has been defined in the context of an active-deductive, object-oriented database language known as CDOL (Comprehensive, Declarative, Object Language). The RTG method studies the contents of rule pairs and rule cycles in a triggering graph and tests for: (1) the successful unification of one rule‘s action with another rule‘s triggering event, and (2) the satisfiability of active rule conditions, asking whether it is possible for the condition of a triggered rule to evaluate to true in the context of the triggering rule‘s condition. If the analysis can provably demonstrate that one rule cannot trigger another rule, the directed vector connecting the two rules in a basic triggering graph can be removed, thus refining the triggering graph. An important aspect in the implementation of the method is the development of a satisfiability algorithm for CDOL conditions. This paper presents the tool that was developed based on the RTG method, describing how techniques from constraint logic programming are integrated with other techniques for testing the satisfiability of rule triggering conditions. The effectiveness of the approach within the context of a sample application is also addressed.

ROL: A deductive object base language

This paper presents a novel deductive object-oriented database language, called ROL (Rule-based Object Language), which is being developed at the University of Regina. ROL effectively integrates important features of object-oriented databases and deductive databases into a uniform framework. It supports object identity, complex objects, classes, class hierarchy, multiple inheritance with overriding, and schema. It also supports structured values such as functor objects and sets, treats them as first class citizens, and provides powerful mechanisms for representing both partial and complete information on sets. It is an extension of pure valued-oriented deductive languages such as Datalog and LDL (without grouping) and subsumes them as special cases. Another novelty is the introduction of a new ordering which can capture the intended semantics of nested sets. The ROL language is given a logical semantics based on this new ordering that accounts in a clean and declarative fashion for all of its object-oriented and value-oriented features as well as the usage of schema in a deductive framework.

Response to the ODMG-93 commentary written by Dr. Won Kim of UniSQL, Inc.

In the March 1994 issue of the ACM SIGMOD Record, Dr. Won Kim of UniSQL and the SIGMOD Chairperson published “Observations on the ODMG-93 Proposal for Object-Oriented Database Language” (Volume 23, Number 1). This commentary contained some useful technical contributions. We thank Dr. Kim for that. Nevertheless, it also contained a number of inaccuracies and misleading statements that we, the ODMG, would like to set straight.

Observations on the ODMG-93 proposal for an object-oriented database language

Observations on the ODMG-93 proposal for an object-oriented database language

Simulative representation of biological knowledge using object-oriented database language

Simulative representation of biological knowledge using object-oriented database language

Object-oriented query language facilitating construction of new objects

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.

DOODLE: a visual language for object-oriented databases

In this paper we introduce DOODLE, a new visual and declarative language for object-oriented databases. The main principle behind the language is that it is possible to display and query the database with arbitrary pictures . We allow the user to tailor the display of the data to suit the application at hand or her preferences. We want the user-defined visualizations to be stored in the database, and the language to express all kinds of visual manipulations. For extendibility reasons, the language is object-oriented. The semantics of the language is given by a well-known deductive query language for object-oriented databases. We hope that the formal basis of our language will contribute to the theoretical study of database visualizations and visual query languages, a subject that we believe is of great interest, but largely left unexplored.

Important features of Iris OSQL

OSQL is the object-oriented database language developed for the Iris object-oriented database management system at Hewlett-Packard Laboratories. Its three fundamental constructs are objects, types, and functions. This paper provides an overview of the underlying concepts and some important features of OSQL.

Towards a deductive object-oriented database language

A language for databases with sets, tuples, lists, object identity and structural inheritance is proposed. The core language is logic-based with a fixpoint semantics. Methods with overloading and methods evaluated externally providing extensibility of the language are considered. Other important issues such as updates and the introduction of explicit control are discussed.