Object-oriented Database Design Research Articles

Conceptual design of object-oriented databases for fuzzy engineering information modeling

Conceptual data modeling is essential for engineering applications. IDEF1X (Integration Definition for Information Modeling) data model provides a formal framework for consistent modeling of the data necessary for the integration of various functiona

产品质量安全案例收集系统设计与实现<br>Safety Product Quality Safety Case Collection System Design and Implementation

产品案例信息收集是进行产品质量安全风险评估和预警的必要前提，通过系统性地收集、分析、汇总各类信息，为后续产品质量安全评估过程奠定基础。本文以寻找产品质量安全因子为核心，搭建了产品质量安全案例收集系统。本论文通过需求分析、UML面向对象建模、数据库设计，实现了该收集系统，并进行展示。该系统在实际运行中，得到了专家的一致认可，并且体现了其案例收集的重要作用。Product quality safety information collection, which lays the foundation for the later evaluation process by collecting, analyzing and summarizing information systematically, is very necessary for the risk evaluation and warning of product quality safety. Aiming at finding the core factors of product quality safety, the paper constructs product quality safety case collection system. The paper displays the system after re- quirement analysis, UML object-oriented modeling and database design. According to the actual running, the system has performed its vital role and got the experts’ unanimous ratification.

Fundamentals of Object Databases: Object-Oriented and Object-Relational Design

Object-oriented databases were originally developed as an alternative to relational database technology for the representation, storage, and access of non-traditional data forms that were increasingly found in advanced applications of database technology. After much debate regarding object-oriented versus relational database technology, object-oriented extensions were eventually incorporated into relational technology to create object-relational databases. Both object-oriented databases and object-relational databases, collectively known as object databases, provide inherent support for object features, such as object identity, classes, inheritance hierarchies, and associations between classes using object references. This monograph presents the fundamentals of object databases, with a specific focus on conceptual modeling of object database designs. After an introduction to the fundamental concepts of object-oriented data, the monograph provides a review of object-oriented conceptual modeling techniques using side-by-side Enhanced Entity Relationship diagrams and Unified Modeling Language conceptual class diagrams that feature class hierarchies with specialization constraints and object associations. These object-oriented conceptual models provide the basis for introducing case studies that illustrate the use of object features within the design of object-oriented and object-relational databases. For the object-oriented database perspective, the Object Data Management Group data definition language provides a portable, language-independent specification of an object schema, together with an SQL-like object query language. LINQ (Language INtegrated Query) is presented as a case study of an object query language together with its use in the db4o open-source object-oriented database. For the object-relational perspective, the object-relational features of the SQL standard are presented together with an accompanying case study of the object-relational features of Oracle. For completeness of coverage, an appendix provides a mapping of object-oriented conceptual designs to the relational model and its associated constraints.

Vertical Fragmentation in Databases Using Data-Mining Technique

A new approach to vertical fragmentation in relational databases is proposed using association rules, a data-mining technique. Vertical fragmentation can enhance the performance of database systems by reducing the number of disk accesses needed by transactions. By adapting Apriori algorithm, a design methodology for vertical partitioning is proposed. The heuristic methodology is tested using two real-life databases for various minimum support levels and minimum confidence levels. In the smaller database, the partitioning solution obtained matched the optimal solution using exhaustive enumeration. The application of our method on the larger database resulted in the partitioning solution that has an improvement of 41.05% over unpartitioned solution and took less than a second to produce the solution. We provide future research directions on extending the procedure to distributed and object-oriented database designs.

Optimal Design of Object-Oriented Databases in Automatic Information-Control Systems. I. Analysis of Problem Domains

Design of object-oriented databases for automatic information control systems is studied. A formal method of analysis and design of optimal structures for object-oriented databases is developed on the basis of sequential interconnected formalizations of user problem domains, clustering of user information and functional requirements, design and analysis of object models for user requirements and object canonical structure of databases and design of optimal logical structures for object-oriented databases. Methods of analysis of problem domains of database users and construction of effective object canonical database structures in the form of classes, objects, and their relations and satisfying principles of abstraction, encapsulation, modularity, and hierarchy are described.

Development of a magnetospheric state-based trapped radiation database

At the core of any empirical trapped radiation model is a database containing energetic particle observations. The usefulness of such a database and the performance of the resulting models depend on the database flexibility to respond to queries based on differing magnetospheric conditions, and the ability to locate, select, retrieve and analyze the relevant particle data. Current empirical trapped radiation models, such as the NASA AE-8 and AP-8 models, are essentially flux lookup tables on ( E; B/ B 0, L) grids based on processed data. Such lookup tables are inherently static, non-updateable, and non-extensible. Consequently, the models constructed from them would have limited performance. As an initial effort to construct a new generation of empirical trapped radiation models, a new magnetospheric state-based trapped radiation database is being constructed in order to overcome existing model limitations. We have adopted an object-oriented database design to accommodate the complex and dynamic space radiation environment. The technique encapsulates the particle data, ancillary data, and metadata into abstract objects in a common framework to handle heterogeneous data sources. The new database structure will allow users to query the database using combinations of geophysical, temporal and spatial parameters. In this paper, we will focus on the implementation issues that arise in integrating heterogeneous data sets. To mitigate against early obsolescence when updated or new data become available, the models’ underlying database must be updateable and extensible. In addition, to ensure high model performance, the database must be parameterizeable, so that the selection of data from the database for analysis or modeling can vary with magnetospheric conditions or states that vary with solar wind and IMF driving conditions and geomagnetic responses (see Fung, S. F. Recent development in the NASA trapped radiation models, in: Radiation Belts: Models and Standards, Geophys. Monogr. Ser., vol. 97, American Geophysical Union, Washington, DC, pp. 79–91, 1996). By following an object-oriented design, the new trapped-radiation database can be easily updated, extended and re-parameterized. Our effort in constructing a prototype particle radiation database will be applicable to the NASA Living With a Star Program.

Adding inclusion dependencies to an object-oriented data model with uniqueness constraints

We study an object-oriented data model that allows to express both uniqueness constraints and inclusion dependencies as semantic constraints. The data model is based on a subset of F-logic. Uniqueness constraints comprise path functional dependencies which generalise functional dependencies and reflect the navigational power of object-oriented query languages. As inclusion dependencies, we consider explicit class inclusion constraints, besides inclusions required by class hierarchies, and onto constraints that enforce reachability of objects. For these classes of semantic constraints we present an axiomatisation and prove its inference rules to be correct and complete with respect to general logical implication, leaving the decision problem open. The completeness proof combines the known construction for path functional dependencies alone with a possibly infinite model generation process to enforce onto constraints. The results prepare the grounds for normal forms in object-oriented data models and subsequently for computer aided object-oriented database design, following the decomposition approach for the relational data model. Beyond the application for schema design, the achievements could also be exploited for related tasks like semantic query optimisation and mediated data integration within a variety of graph based data models.

Behavior-consistent specialization of object life cycles

Object-oriented design methodologies represent the behavior of instances of an object type not merely by a set of operations, but also by providing an overall description on how instances evolve over time. Such a description is often referred to as "object life cycle."Object-oriented systems organize object types in hierarchies in which subtypes inherit and specialize the structure and behavior of their supertypes. Past experience has shown that unrestricted use of inheritance mechanisms leads to system architectures that are hard to understand and to maintain, since arbitrary differences between supertype and subtype are possible. Evidently, this is not a desirable state of affairs and the behavior of a subtype should specialize the behavior of its supertype according to some clearly defined consistency criteria. Such criteria have been formulated in terms of type systems for semantic data models and object-oriented programming languages. But corresponding criteria for the specialization of object life cycles have so far not been thoroughly investigated.This paper defines such criteria in the realm of Object Behavior Diagrams, which have been originally developed for the design of object-oriented databases. Its main contributions are necessary and sufficient rules for checking behavior consistency between object life cycles of object types in specialization hierarchies with multiple inheritance.

An object-oriented database design for improved performance

Object-oriented databases (OODBs) are known to be rich in functionality but poor in performance. One of the important factors that affect performance is the physical database design. We developed a methodology for the design of an efficient storage structure of OODB that minimizes the database operating costs. The input for our method is the logical OODB schema and set of user transactions of retrieval and update types. The output of our method is the determination of which instance variables should be inherited from direct and indirect superclasses and stored in which subclasses. We used a genetic algorithm (GA) to solve this intractable problem. The methodology was applied on a university database. Compared to previous storage models, the storage model produced with our methodology showed database performance improvement ranging from 26% to 31%, on the average. Our results demonstrate a cost-effective storage structure design that boosts the operating performance of OODBs.

Bottom-up design of active object-oriented databases

Bottom-up design of active object-oriented databases

Conceptual design of fuzzy object-oriented databases using extended entity-relationship model

Entity-relationship–extended entity-relationship models play a crucial role in the conceptual design of relational databases as well as object-oriented databases. Recently, several approaches have been proposed to enhance object-oriented databases (OODBs) using fuzzy set theory. In this paper, we introduce a fuzzy extended entity-relationship model to cope with imperfect as well as complex objects in the real world at a conceptual level. In particular, we provide the formal approach to mapping a fuzzy extended entity-relationship model to a fuzzy object-oriented database schema. © 2001 John Wiley & Sons, Inc.

FHIN: an efficient storage structure and access method for object-oriented databases

While relational database technology has dominated the database field for more than a decade, object-oriented database (OODB) technology has recently gained a lot of attention in the database community. Many researchers are concerned about the performance of OODBs. This paper proposes an OODB design methodology called fragmented hash-indexed (FHIN) that is aimed at improving the operating performance of OODBs. The FHIN model's storage structure contains an Instances–Classes Table (ICT) with a two-segment data design. Query processing is done by accessing data segments through ICT with an algorithm introduced here. The FHIN model uses three access methods: hashing, indexing, or hash-indexing. The database performance of FHIN is compared to two previous access methods using 1050 simulation runs. Results indicate that the FHIN model is 43% better than either of the other models in smaller databases, 65% better in larger databases, 50% better under conditions of high updating, and 72% better under conditions of low updating. These results suggest that FHIN methodology has promise and is worthy of exploration and OODB software development.

An Empirical Analysis of the Object-Oriented Database Concurrency Control Mechanism O2C2

Object-oriented databases are becoming increasingly popular in business. Some areas of research interest include formal object-oriented database models, query optimization, analysis and design techniques, and concurrency control. Many of these issues have been well researched as they pertain to the relational model and to centralized databases. Specifically, many studies have concentrated on relational database concurrency control but few have concentrated on object-oriented database concurrency control. Once a concurrency control mechanism is proposed and implemented, the next phase is to analyze its performance using simulation techniques. This paper includes the simulation study for the object-oriented database concurrency control mechanism named O2C2. Contributions of this study include offering a method of simulating concurrency control in an object-oriented database model. This includes extending prior studies that deal only with reading or writing a single data item without implications to the rest of the database. Specifically, the method of simulating concurrency control in an object-oriented database model is applied to the mechanism O2C2. The simulation demonstrates some intuitive, yet important properties about concurrency control in object-oriented databases. For example, as the mix of transactions progresses from operating mostly with instance objects to operating with more class and method definitions, throughput decreases.

Modeling collaborative behavior using cooperation contracts

Several objects exhibit collaborative behavior if they act together in answering a message they have received jointly. Collaborative behavior is defined by cooperation contracts which are established between several object classes and which declare a set of cooperative methods. A cooperative method is invoked by a cooperative message sent to a tuple of instances, one for each object class in the cooperation contract. This extends the traditional message passing paradigm which requires the receiver of a message to be a single object only. Cooperation contracts offer several benefits for behavior modeling in object-oriented database design. Behavior provided by several object classes in concert needs not be dispersed and can be defined in a single place. Therefore, behavior designs become symmetric, more maintainable and better extensible. Cooperation contracts can easily be made available as beneficial modeling constructs in existing object-oriented database management systems by adding a few classes. This paper presents such an extension based on the commercial object-oriented database management system GemStone.

Design of object-oriented database for the definition of machining operation sequences of 3D workpieces

This paper describes the activities of Object-Oriented (OO) analysis that were implemented in order to obtain a high part representation level and to give sets of structured and hierarchical data to the Computer Aided Process Planning (CAPP) system. The OO modeling activities were carried out by using the Object-Oriented System Analysis (OOSA) method which allows careful specification of all the information contained inside the system. All the models used by this method have been described in detail to show how the OO database is defined and how it can be used by a generative CAPP system. The feature model proposed is defined by taking all the part information that can be recognized and extracted from the Computer Aided Design (CAD) model into account. The result is the design of an OO database which allows the CAPP system to use manufacturing features to define machining operation sequences of 3D workpieces. The approach proposed is generic enough to integrate any geometrical forms which can be recognized and identified from the CAD system. Hole geometry is taken as an example to show the link between the step of OO analysis and the step of knowledge representation in the Expert System which has been used to generate machining cycles. The OO database presented makes up a real solution of CAD/CAPP/CAM integration by using feature modeling.

Conceptual object-oriented database: A theoretical model

The evolution of object-oriented databases (OODBs) has not been accompanied by an equivalent evolution of theoretical models, leaving the foundations for OODBs ill-defined. Design of OODBs has been hampered by the lack of design techniques/tools which correspond to the theoretical model. This paper defines a core conceptual object-oriented database (COODB) model providing a foundation and framework for theoretical research. Structural and behavioral definitions for an object, a class, and a class hierarchy are given. A specification hierarchy is introduced as a design tool, and a messaging component is defined which enables asynchronous and synchronous interaction.

Using NNF to transform conceptual data models to object-oriented database designs

More work is needed on devising practical, but theoretically well-founded procedures for doing object-oriented database (OODB) design [17]. Design procedures should also be flexible enough to take into account various application characteristics (such as whether objects are very large or are read-only). In this paper, we present and discuss an OODB design procedure that addresses these problems. The procedure is practical in the sense that it is based on a common family of conceptual models and in the sense that it does not expect users to supply esoteric, difficult-to-discover, and hard-to-understand constraints (such as multivalued dependencies), nor does it make hard-to-check and easy-to-overlook assumptions (such as the universal relation scheme assumption). At the same time, the procedure is well-founded and formal, being based on NNF (Nested Normal Form [21]), a new theoretical result that characterizes properties of interest in designing complex objects. It is also adaptable to various applications characteristics.

Selected Issues in Object-oriented Database Design

In order to build robust applications that are able to perform well using object-oriented database technology, a range of factors must be considered. This paper examines some of the more important of these, such as scalability, method execution location, locking strategy and data integrity. It attempts to give general guidance to the designer, emphasising the importance of physical database design and integration with other database and distributed-object technologies.

Conceptual modelling-based design of object-oriented databases

The focus of this article is the transformation of conceptual data models (such as ER, NIAM and PSM) to object-oriented databases. This transformation is captured within the framework of a two-level architecture. Conceptual models are first mapped to abstract intermediate specifications, which are then transformed to database schemas in a given object-oriented database environment. This enables us to treat different target systems in a uniform way. As final implementation environments, we consider object-oriented as well as object-relational DBMSs, including the SQL3 and ODMG-93 standards. We do not reveal the specific details of these standards. Rather, we use intermediate representations expressed in F-logic, a logic-based abstract specification language for object-oriented systems. Several transformation alternatives are discussed in a formal context, resulting in a collection of design options.

MOODD, a method for object-oriented database design

In this paper we propose a Method for Object-Oriented Database Design, called MOODD. Considerable recent research [22] has focused on object-oriented design techniques. MOODD distinguishes itself by generating an object-oriented data definition from requirements written in a natural language. Examples to illustrate the method are given for a particular OODBS called O2 [19]. MOODD consists of three phases. The first phase is to use a Requirement Specification Language (RSL) [27] to represent user requirements. Next, the RSL requirements are converted into an object-oriented conceptual model composed of the Nested Entity-Relationship (NER) [10]/ Update Protocol Model (UPM) [9]. Finally, the NER/UPM schemas are implemented by an object-oriented data model.