Preci* is a generalised distributed database management system, capable of supporting heterogeneous, pre-existing databases as nodes. The system is fully decentralised, supporting both retrieval and update of the data. Varying degrees of location transparency can be provided, according to user requirements. The work presented here is concerned with data integration and query decomposition. An extended relational algebra (PAL) is developed, which serves both as a query language and as a mapping language for data integration. The suitability of PAL for data integration is demonstrated by a number of examples, and by comparison with existing proposals. A major attraction of PAL is that it can also be used as a query language, thereby making query decomposition much easier. The relational algebraic approach is shown to be particularly appropriate for query decomposition, since queries can be easily parsed and represented in tree form. Such parse trees are readily transformed to yield equivalent expressions which will execute more efficiently. An algorithm is given for decomposing global PAL queries into nodal subqueries, and for coordinating their execution. The general problem of allocating subqueries to execution nodes is not tackled, though it is shown that the algorithm will do this allocation under specific implementation conditions. A prototype of Preci* has been implemented in 'C'.

The upsurge in the number of casual users and the general acceptance of computer technology has shown that the principal driving force in software engineering is shifting from functionality to usability. It has also become evident that the desktop metaphor and its whole related genre do not provide the modern interface designer with the expressive power that is needed. Nowhere is a new approach more needed than in interfaces for databases. Previous studies in interface design for database management systems have attempted to use solely the desktop metaphor. We have used three dimensional graphical techniques to construct an interface, called <I>Amaze</I> for our object oriented database <I>P/FDM</I>. Interactive animated 3D graphics have been embedded inside a standard menu driven framework. Using 3D graphics new metaphors have been developed to aid the user interaction. Our development has taken a modular approach, which allowed us to develop a number of different visualisations for query construction, the structure of the database and result representation. It is possible to view the data using a number of multimodal displays (a number of customised multimodal displays have been built). <I>Amaze</I> has been used on a variety of different data sets (including a protein structure database, a personnel database and an antibody database). These databases differ greatly in size and complexity of their semantics. The work discussed in this thesis suggests an alternative approach to user interface design for database systems, it introduces the idea of <I>Database Visualisation</I> and suggests novel mechanisms for computer interaction using 3D graphics.

Almost all of the database products developed over the past few years are based on what is called the relational approach.The purpose of this thesis is to characterize a relational data base management system, we do this by studying the relational model in some depth.The relational model is not static, rather it has been evolving over time. We trace the evolution of the relational model. We will also consider the ramifications of the relational model for modern database systems. / Department of Computer Science

No description available.

A materialized view is a derived data collecton stored in a database. When the source data for a materialized view is updated, the materialized view also needs to be updated. The process of updating a materialized view in response to changes in the source data is called view maintenance. There are two methods for maintaining a materialized view - recomputation and incremental computation. Recomputation computes the new view instance from scratch using the updated sources data. Incremental computation on the other hand, computes the new view instance by using the update to the source data, the old view instance, and possibly some source data. Incremental computation is widely accepted as a less expensive mathod of maintaining a view when the size of the update to the source data is small in relation to the size of the source data. / Thesis (PhD)--University of South Australia, 2000

No description available.

Thesis (M.S.)--Rochester Institute of Technology, 1989. / Includes bibliographical references.

Thesis (Ph. D.)--University of New South Wales, 1997. / Also available online.

Report (M.S.)--Virginia Polytechnic Institute and State University, 1994. / Vita. Abstract. Includes bibliographical references (leaves 54-56). Also available via the Internet.

Thesis (M.C.S.)--Carleton University, 2003. / Includes bibliographical references (p. 150-156). Also available in electronic format on the Internet.