ADO: An Active Distributed Object-Oriented Database Model

Object-oriented databases are emerging as a newgeneration database technology for complex applications. In this paper, we present an active distributed object-oriented (ADO) database model, which can capture not only passive behaviors but also active behaviors of complex objects. Besides, the distribution nature of objects can be reflected from within the model as well. Based on the model, we have developed a prototype active distributed object-oriented database management system, and applied it to a housing property management application

Information system analysis: design consideration of active database / Sharina Mohd Nasir

In the rapidly changing environment of the knowledge economy, an enterprise must respond to potential fiiture changes when developing and implementing enterprise systems, which must be thus flexible and integrateable. The concepts of virtual enterprise, supply chain and B2B e-business have been widely employed in business development. Since the essence of these concepts is "enterprise integration", the importance of information sharing among enterprises is increasing. This research is meant to look at the core of this integration and sharing environment; the active databases system design by which active database is a database technology for supporting application in heterogeneous information system. This research presents the result of an empirical study of design consideration of data model for the active databases in the enterprise environment. The objectives of this study are to identify the roles and functionalities of active databases, the most common data model being used for active databases and the recommendation of the optimized data model for active databases. The researcher has conducted interview sessions with 7 selected companies from various business areas to get the primary data by using a set of questionnaires as the research instrument. The results indicate that the most common type of data model being used by the involved companies is relational data model and followed closely by object-oriented data model. The results also reveal that the roles and functionalities of active databases being implemented includes to supply data at real-time, to detect event, to execute rules, and for provisioning. The recommended optimized data model for active databases is object oriented data model by which it generates more advantages differed to the relational data model. This research also provides several recommendations at the final section of the report that should be considered upon this research

Implementing Associations among Classes in an Environment of Active Databases

The association is a native concept from relational databases, one that has been adapted to object oriented (OO) modelling. It is an interesting operator used to describe links among objects of a system, commonly included in the most popular diagram-based OO methodologies. However, those methodologies sometimes present a lack of formality that may undermine its use. In this paper we formalize the semantics of associations. Firstly, we will describe an OO model based on different kinds of constraints. Some of them will be especially useful for describing the semantics of associations. Finally, we will present some remarks about implementation by means of triggers, a new feature incorporated in databases to specify an inner active behavior.Comisión Interministerial de Ciencia y Tecnología TIC97-0593-C05-0

Learning from AI : new trends in database technology

Recently some researchers in the areas of database data modelling and knowledge representations in artificial intelligence have recognized that they share many common goals. In this survey paper we show the relationship between database and artificial intelligence research. We show that there has been a tendency for data models to incorporate more modelling techniques developed for knowledge representations in artificial intelligence as the desire to incorporate more application oriented semantics, user friendliness, and flexibility has increased. Increasing the semantics of the representation is the key to capturing the "reality" of the database environment, increasing user friendliness, and facilitating the support of multiple, possibly conflicting, user views of the information contained in a database

State-of-the-art on evolution and reactivity

This report starts by, in Chapter 1, outlining aspects of querying and updating resources on the Web and on the Semantic Web, including the development of query and update languages to be carried out within the Rewerse project. From this outline, it becomes clear that several existing research areas and topics are of interest for this work in Rewerse. In the remainder of this report we further present state of the art surveys in a selection of such areas and topics. More precisely: in Chapter 2 we give an overview of logics for reasoning about state change and updates; Chapter 3 is devoted to briefly describing existing update languages for the Web, and also for updating logic programs; in Chapter 4 event-condition-action rules, both in the context of active database systems and in the context of semistructured data, are surveyed; in Chapter 5 we give an overview of some relevant rule-based agents frameworks

Maintaining consistency in distributed systems

In systems designed as assemblies of independently developed components, concurrent access to data or data structures normally arises within individual programs, and is controlled using mutual exclusion constructs, such as semaphores and monitors. Where data is persistent and/or sets of operation are related to one another, transactions or linearizability may be more appropriate. Systems that incorporate cooperative styles of distributed execution often replicate or distribute data within groups of components. In these cases, group oriented consistency properties must be maintained, and tools based on the virtual synchrony execution model greatly simplify the task confronting an application developer. All three styles of distributed computing are likely to be seen in future systems - often, within the same application. This leads us to propose an integrated approach that permits applications that use virtual synchrony with concurrent objects that respect a linearizability constraint, and vice versa. Transactional subsystems are treated as a special case of linearizability