After a decade of major technical and theoretical advancements in the area, the scope for exploitation of database technology has never been greater. Neither has the challenge. This volume contains the proceedings of the 17th British National Conference on Databases (BNCOD 2000), held at the University of Exeter in July 2000. In selecting the quality papers presented here, the programme committee was p- ticularly interested in the demands being made on the technology by emerging application areas, including web applications, push technology, multimedia data, and data warehousing. The concern remains the same: satisfaction of user - quirements on quality and performance. However, with increasing demand for timely access to heterogeneous data distributed on an unregulated Internet, new challenges are presented. Our three invited speakers develop the theme for the conference, considering new dimensions concerning user requirements in accessing distributed, hete- geneous information sources. In the ?rst paper presented here, Gio Wiederhold re?ects on the tension between requirements for, on the one hand, precision and relevance and on the other completeness and recall in relating data from heterogeneous resources. In resolving this tension in favour of the former, he maintains that this will fundamentally a?ect future research directions. Sharma Chakravarthy adds another dimension to the requirement on inf- mation, namely timeliness. He shares a vision of just-in-time information de- vered by a push technology based on reactive capabilities. He maintains that this requires a paradigm shift to a user-centric view of information.

Invited Papers.- Precision in Processing Data from Heterogeneous Resources.- Just-in-Time Information: To Push or Not to Push.- Performance and Optimisation.- Using Space-Filling Curves for Multi-dimensional Indexing.- A Multi-Query Optimizer for Monet.- Join Order Selection ( Good Enough Is Easy ).- User Requirements on Large Systems.- A User-Centric View of Data Warehouse Maintenance Issues.- VESPA: A Benchmark for Vector Spatial Databases.- Collection Views: Dynamically Composed Views Which Inherit Behaviour.- Distributed Transactions.- Global Transaction Termination Rules in Composite Database Systems.- A Review of Multidatabase Transactions on the Web: From the ACID to the SACReD.- A Publish/Subscribe Framework: Push Technology in E-Commerce.- Invited Paper.- Characterizing Data Provenance.- Interoperability Using XML.- A Grammar Based Model for XML Schema Integration.- CORBA and XML: Design Choices for Database Federations.- Rewriting XQL Queries on XML Repositories.