Database Application Development Research Articles

A comparative case study of three database application development environments

This paper describes an exploratory case study that investigates the claim that the object-oriented approach to information systems development reduces development effort and improves maintainability. Software metrics for development effort, complexity, and maintainability of three functionally similar 4GL database development environments, one objected-oriented and two traditional (relational) are compared. The results indicate that programs developed using the object-oriented environment needed fewer lines of code, had less volume, required less effort, were less complex and were more maintainable than those developed using the traditional 4GL environments.

On the Formal Specification and Derivation of Relational Database Applications

The development of database applications is usually carried out informally. The derivation of database programs directly from formal specifications is a well known and unsolved problem. Most of the previous work on the area either tried to solve the problem too generally or was restricted to some trivial aspects, for example deriving the database structure and/or simple operations. However difficult in general, deriving relational database applications directly from Z specifications satisfying a certain set of rules (the method) is not arduous. With appropriate tool support, writing formal specifications according to the method and deriving the corresponding relational database programs can be straightforward. Moreover, it should produce code which is standardized and thus easier to understand and maintain.This paper summarizes material from my Ph.D. thesis [4]. Therefore, it is a pleasure to thank again my supervisors, Ray Welland and David Harper. The financial support for the Ph.D. course was provided by CAPES (Brazilian Federal Agency for Postgraduate Education) and by UFPE (Federal University of Pernambuco).

A cooperative learning approach to database group projects: integrating theory and practice

This paper describes the use of cooperative learning concepts in support of an introductory database management course that emphasizes the theoretical and practical aspects of database application development. The database practice is realized through the use of cooperative group projects. The course project is divided into three main phases, involving requirements analysis and conceptual design, relational database mapping and prototyping, and database system implementation using Microsoft Access/sup TM/. Students are required to actively participate in each phase, with students assuming different roles in each phase to allow them to experience different leadership responsibilities. This paper also describes a cooperative learning approach to integrating the practical use of a database product into the theoretical curriculum of a database management course. The paper concludes with a detailed evaluation of the group projects effect on the student's performance in the class.

Building a database design laboratory on the Internet

Commercial tools for software engineering include many development environments to support the design process. These integrated tools are usually distributed through traditional retail channels, with vendors increasingly giving customers the option of downloading products from the Web. The tools are installed on user client machines and are usually duplicated for actual tool use at customer sites. Users are responsible for installation, maintenance and upgrade procedures. We developed Web Lab as part of a project sponsored by the European Commission to advance rule-based, object-oriented technologies for developing database applications. The Web Lab was designed to help disseminate the research results. It enables remote use of a design environment for database applications, including a repository for application development that provides a protected workspace. However, as software becomes more and more a commodity, we expect vendors to begin selling software use rather than tools, an option that is particularly attractive in the context of thin clients running on network computers. Web Lab demonstrates the feasibility of this idea for commercial software distribution. We describe the Web Lab project, its implementation, and plans for further development.

A Scaleable, Database Architecture for Storage of PVT Data

Summary Convenient access to fluid-property data in electronic form is currently not available in many petroleum organizations. Ready access to this information could result in significant cost savings by reducing the need for repeated studies and reducing the scope of new studies by analogous fluid evaluation. This work presents an overview of the development of a new scaleable database application to address these issues. In addition, we discuss design and development issues related to database scaleability. The application, PVT ReCORD, is currently undergoing beta testing by a major commercial laboratory that is creating an on-line fluid-property repository and automating pressure/volume/temperature (PVT) report generation with this tool.

Automatic GUI generation from database schema information

In recent years, many database application development tools have appeared which focus on multimedia databases. Although many of these tools maintain a function that generates a default GUI screen from the database schema, the design of the screen layout is over simplified and inadequate. To make GUIs with elaborate designs and layouts, we have developed an automatic GUI layout generation system. This system generates various GUI components and lays them out on a screen by simulated annealing loops. In this paper, the internal data structures are explained. In addition, the descriptive power of our system, perturbation operations, and its evaluation measures are also described. © 1997 Scripta Technica, Inc. Syst Comp Jpn, 28(5): 1–10, 1997

A practical guide for implementing data warehousing

Data warehousing is a method by which an organization stores its data so that the information contained in that data can be ascertained, accessed and analyzed more quickly and efficiently than would be possible when using a conventional architecture. Multidimensional databases (MDD) provide an efficient means to analytical processing, but the cost is prohibitive for many small and mid-sized organizations. This paper addresses the need for an inexpensive solution to an information management problem that can be solved by database application developers using conventional tools. A relational database management system (RDBMS) can be used to emulate a MDD and still maintain an acceptable performance level in a client server environment.

Distributed database access in a corporate environment using Java

Most of the Java applets on the Web today are developed primarily for visualization and 3D interactive animation. Serious doubts have been raised about the feasibility of using Java in the domain of enterprise applications. Compared with the conventional CGI-based approach for developing database applications, Java-based approach provides a high degree of flexibility, scalability, portability and robustness. Through the use of HORB, a software tool based on the concept of Object Request Broker, Java client and server objects can be created easily and accessed transparently. A methodology using Java and HORB for developing database applications is proposed, with the objective to establish a robust Web infrastructure in a corporate environment.

Database theory in practice

This paper describes the use of cooperative group learning concepts in support of an undergraduate database management course that emphasizes the theoretical and practical aspects of database application development. The course project is divided into three main phases, involving requirements analysis and conceptual design, relational database mapping and prototyping, and database system implementation using Microsoft Access. The project deliverables are designed so that students not only develop a database implementation, but also evaluate their design in terms of functional dependencies, normal forms, the lossless join property, and the dependency preservation property, thus establishing the need for sound database design principles. Students are required to actively participate in each phase, with students assuming different roles in each phase to allow them to experience different leadership responsibilities. As part of the grading process, students evaluate their own performance as well as the performance of others in the group. This paper describes our experience with the structure and administration of cooperative groups and provides a discussion of the lessons we have learned, including initial observations of the effectiveness of the approach.

SQLGEN: A framework for rapid client-server database application development

SQLGEN is a framework for rapid client-server relational database application development. It relies on an active data dictionary on the client machine that stores metadata on one or more database servers to which the client may be connected. The dictionary generates dynamic Structured Query Language (SQL) to perform common database operations; it also stores information about the access rights of the user at log-in time, which is used to partially self-configure the behavior of the client to disable inappropriate user actions. SQLGEN uses a microcomputer database as the client to store metadata in relational form, to transiently capture server data in tables, and to allow rapid application prototyping followed by porting to client-server mode with modest effort. SQLGEN is currently used in several production biomedical databases.

SQLGEN: A framework for rapid client-server database application development

SQLGEN is a framework for rapid client-server relational database application development. It relies on an active data dictionary on the client machine that stores metadata on one or more database servers to which the client may be connected. The dictionary generates dynamic Structured Query Language (SQL) to perform common database operations; it also stores information about the access rights of the user at log-in time, which is used to partially self-configure the behavior of the client to disable inappropriate user actions. SQLGEN uses a microcomputer database as the client to store metadata in relational form, to transiently capture server data in tables, and to allow rapid application prototyping followed by porting to client-server mode with modest effort. SQLGEN is currently used in several production biomedical databases.

Enterprise Objects Framework

Today's information system executives desperately need to improve programmer productivity and reduce software maintenance costs. They are demanding flexibility in frameworks and architectures in order to meet unforeseen changes (see [Yankee 94] ). Adaptability is a major requirement of most company's information systems efforts. Management of change is one of the key computing concepts of the 1990s.Object-oriented tools and development frameworks are starting to deliver the benefits of increased productivity and flexibility. These next-generation products now need to be combined with relational databases to leverage investments and facilitate access to business data. Object-Relational Enablers automate the process of storing complex objects in a relational database management system (see [Aberdeen 94] ).The Enterprise Objects Framework product is a second generation product bringing the benefits of object-oriented programming to relational database application development. Enterprise Objects Framework enables developers to construct reusable business objects that combine business logic with persistent storage in industry-standard relational databases. Enterprise objects are first class citizens in the NEXTSTEP and OpenStep developer and user environments. They can be geographically distributed throughout heterogeneous servers within an enterprise using the Portable Distributed Objects product (see [NeXT-DO 94] ).In this extended abstract we first describe the enterprise object distribution model and then give a brief synopsis of how relational data is mapped into objects. We then present an outline of the system architecture, explain how objects are mapped to multiple tables, and summarize the transaction semantics as well as the application development life-cycle. We conclude with an outlook on future development.

Group data base design: Addressing the view modeling problem

Today's organizations increasingly depend on the use of data base technology to manage their operations. Advances in technology have resulted in increasing the number and complexity of these data bases. Despite their growing complexity, all data bases have one thing in common: each must have gone through either a formal or an informal design process. Data bases must mirror reality accurately, and thus the design process must better capture that reality. The heart of the design process is the conceptual design, data model mapping, and physical design. Our research focuses on providing automated support for the first of these, e.g., conceptual design. Conceptual design is known to be a very difficult and time-consuming phase in the development of data base applications. This article describes the architecture, implementation, and use of a distributed graphical group data base design system. The group view modeling system (GVMS) is implemented in Microsoft Windows for networked personal computers. The main purpose of GVMS is to allow multiple designers (or users) to share conceptual design information in real time and resolve design conflicts through the electronic medium. The underlying data model, semantic data model, is extended to include distribution information as well as transactions and is represented as an extended entity relationship model. Diagram management techniques are implemented to aid in simplifying large complex designs. A small study demonstrated that groups of data base designers who define their view collectively outperform individuals.

INDUSTRY AND PRACTICE

This study investigated, in an experimental setting, the understanding and use of object-oriented database design concepts in designing databases. There are many varieties of object-oriented database design techniques and we chose the methodology suggested by Kroenke (1988) for use in the class. This method is expected to simplify the development of database and database applications tremendously (Kroenke, 1988). Through the market for object-oriented database systems is growing, a survey of the literature (in 1992) revealed no empirical investigation of the usefulness of object-oriented database design concepts in organizations or in classrooms.

Client-server trends

The call is out for software developers and information system managers to support the move to mission-critical client-server applications. These are the findings of a survey of 683 of those in attendance at the 1993 Database World and Client-Server World Show. Their responses reflected a multifaceted market-one that is driven by a universal desire for greater programming productivity-and showed that opportunities still abound for developers to seize with previously unthought-of products. As evidenced by the survey, database application development and client-server computing are centered in the vertically integrated industries, which supplied 52 percent of the attendees sampled. Software vendors and computer manufacturers which provide client-server products, made up only 15 percent of the respondents. Attendees were evenly distributed across small, mid-sized, and large organizations. >

MoodView

OODBMSs need more than declarative query languages and programming languages as their interfaces since they are designed and implemented for complex applications requiring more advanced and easy to use visual interfaces. We have developed a complete programming environment for this purpose, called MoodView. MoodView translates all the user actions performed through its graphical interface to SQL statements and therefore it can be ported onto any object-oriented database systems using SQL. MoodView provides the database programmer with tools and functionalities for every phase of object oriented database application development. Current version of MoodView allows a database user to design, browse, and modify database schema interactively and to display class inheritance hierarchy as a directed acyclic graph. MoodView can automatically generate graphical displays for complex and multimedia database objects which can be updated through the object browser. Furthermore, a database administration tool, a full screen text-editor, a SQL based query manager, and a graphical indexing tool for the spatial data, i.e., R Trees are also implemented.

Object-orientation and the SQL standard

The database language standard, SQL, adopted by both ANSI and ISO, is now well established as a language for developing database applications. The SQL standard has been evolving ever since its first adoption in 1986, with new revisions being announced every three years. The latest revision (SQL-92) has just been announced by both ANSI and ISO. Currently, work is underway on the next revision, SQL3, which is expected in 1995–1996 timeframe. A major focus of SQL3 effort is to incorporate an object-oriented type system while maintaining strict upward compatibility with SQL-92. The type system of SQL3 is based on concepts such as abstract data types, object identity, polymorphism, subtypes-supertypes, parameterized types, dynamic binding, etc. In this paper, we report on the current status of SQL3 type system.

Intelligent databases: Old challenges and new opportunities

The evolution of existing information systems and a new wave of data-intensive applications are creating a strong demand for database-centered programming environments much more sophisticated and intelligent than those supported by current database systems. In this paper, we describe the contributions that deductive databases offer to the evolution of databases and information systems to satisfy said demands. In addition to all database essentials, deductive databases support rule-based logic-oriented languages that allow terse formulations of complete applications, along with reasoning and queries. Thus, they support a rule-based interface that eliminates the impedance mismatch problem (between programming language and query sublanguage) and elevates the design and development of database applications to the level of declarative, knowledge-based specifications. In this paper, we review the evolution of the enabling technology and architectures of deductive database prototypes; then we focus on their applications, as seen by the author through his experience with theLDL/LDL++ project. In particular, the paper describes the languages and the (bottom-up) execution technology used by the first generation of deductive database prototypes. Then the paper discusses how the experience with a first-generation system (LDL) guided the design and implementation of a second-generation prototype (LDL++).

DBDesigner

DBDesigner is a graphical front end tool for ONTOS, a commercial object-oriented database system. Through its graphical user interface, DBDesigner allows an application developer to design, browse, and modify a database schema, and to generate C++ header files from the schema. For the purpose of testing and prototyping, DBDesigner permits the user to create, modify, and delete objects in a database. DBDesigner can be a stand alone tool for the design of object-oriented databases or as a library module that can be linked into an application program. The unique approach of DBDesigner is to integrate these activities into a working environment for the development of object-oriented database applications.

A retrospective on database application development frameworks

Four application framework models developed by the author for database application development systems are described. The key feature of these systems is to provide a model for the definition of high level objects that represent interface abstraction that can be used to build an application. Structuring application code around interface objects reduces the conceptual distance between the executing program and its specification. At the same time, good programming practices must be supported (e.g., code modularity, reusable components, and information hiding).