Karel Richta

Object-Relational Database Design: Can Your Application Benefit from SQL:2003?

Traditional database design methods based on information engineering principles and data normalization do not fully apply to SQL:2003 object-relational databases. New design methodologies and tools are needed to support complex data constructs used in todays software engineering practice. There are application domains such as spatial, geographical information systems (GISs) and multimedia applications where the use of object-relational features is mandatory. There are also many other application types that are good candidates for object-relational features, but are frequently implemented using purely relational design as designers hesitate to face the challenges of object-relational design. It can be argued that the use of object-relational features is limited in practice by the lack of design methodologies that can guide database designers in making informed decisions about design choices that involve comparisons of relational and object-relational solutions. In this chapter we discuss object-relational design guidelines and illustrate, using an example, that the object-relational implementation can provide significant benefits simplifying the resulting data structures and the implementation of database queries.

Deriving Triggers from UML/OCL Specification

The term integrity is used to refer to the accuracy or correctness of the data in a database. In other words, integrity involves ensuring that the data stored in the database are in any time correct. The database management system needs to be aware of certain rules that users must not violate. Those rules are to be specified in some suitable language, and have to be maintained in the data catalogue.

Formal specifications and case

Present CASE systems contain usually a set of CASE tools integrated around a repository (CASE - Computer Aided Software Engineering, e.g. [Gan90]). These tools are dedicated to document different aspects of a designed system. The CASE repository serves to maintain a large amount of mutually consistent information. CASE tools enable to employ charming graphical techniques for a system description and documentation.

Adaptive Application Structure Design for Java EE Applications

Adaptive Application Structure (AAS) is such a structure that adjusts itself based on the current context. It brings benefits to end users, as it adapts to their specific personal needs. While applications themselves are designed in a particular way by developers, each user is using a particular application differently. Unfortunately, development complexities rise, which necessarily reflects in the development and maintenance efforts increase. The main aim is to mitigate the efforts and to introduce a novel approach to design AAS. A framework to design ASS-based applications is considered and evaluated.

Usage of Aspect-Oriented Programming in Adaptive Application Structure

Adaptive Application Structure (AAS) is one that changes its structure based on the current context. It brings benefits to end users, cause everyone has its own needs. Also the applications is created in some way by developers, but each user is using the application in different way. In AAS-approach development difficulties appears caused by extended development and maintenance efforts. to implement. This paper considers the Aspect-Oriented Programming (AOP)-based approach for the AAS design.

CellStore: Educational and Experimental XML-Native DBMS

This chapter presents the CellStore project, whose aim is to develop XML-native database engine for both educational and research purposes. In this chapter we discuss the basic concepts of the system and its top-level architecture. Then we discuss individual parts of the systems. The discussion is focused mainly on already finished and tested subsystems — low-level storage (we designed and implemented own binary storage model) naive XQuery implementation, and transaction manager. We plan to extend the system in a way to be used as an experimental back-end for web-based application of Semantic web and specialized XML storages. The whole project is managed with focus on clear object-oriented design and test-driven development.

Using XSL in IS Development

The paper deals with an IS prototyping via XSL-transformation over XML-form of its specification. An IS specification is converted into XML-format. The state and behaviour of IS is expressed as DTD. The semantic part of a specification is converted into XSL-code and used as a rewriting system. The prototyped application is simulated with the help of any Web browser. User requirements are converted into XML-term, which is used to rewrite actual state of IS into a new state with the help of XSL-code. The meaning of user requirements is simulated this way.

SPECIFICATION-DRIVEN MAINTENANCE OF INTEGRITY CONSTRAINTS

The paper deals with a desired shift from the code-driven style of information systems maintenance to a specification-driven one. It means, that an information system is developed and maintained as a specification. Suppose, we have a fully documented information system—we have a conceptual model, a design model and an implementation model. Known hard problem of maintenance is the necessity to maintain all these models in parallel. What we have to do in the present state of art is so called code-driven maintenance—at first, the code of a system is altered, and hopefully the specification will be modified accordingly sometime later. What we are thinking about is the specification-driven maintenance, where changes can be made in the specification and projected (semi-) automatically to other levels. It does not mean there must necessarily exist fully automated tools generating solution from a specification, but any developer’s choice or hint is to be stored together with the specification.

Information Systems Development via Model Transformations.

Many present systems can be developed by a sequence of transformations from the source specification to the final implementation. An interesting question is whether we can support such a sequence of transformations by some formal apparatus that enables to verify succeeding steps of development, and finally also the whole development process. As an example, we use the transformation of a definition of the set of autonomous agents by classical workflow models and then transform them into a set of Petri nets. Such transformation would support development of software systems, whose specification is based on classical workflow models, but the implementation is based on Petri nets. Each part of the designed system is translated from workflow model into Petri nets, and interpreted by the special Petri Nets Virtual Machines, which are installed on all nodes of the system.

Database Architectures: Current State and Development

The paper presents shortly a history and development of database management tools in last decade. The movement towards a higher database performance and database scalability is discussed in the context to requirements of practice. These include Big Data and Big Analytics as driving forces that together with a progress in hardware development led to new DBMS architectures. We describe and evaluate them mainly in terms of their scalability. We focus also on a usability of these architectures which depends strongly on application environment. We also mention more complex software stacks containing tools for management of real-time analysis and intelligent processes.