Metadata: An Overview And Some Issues

INTRODUCTION 1.1 Problem Statement There are large problems for information systems today. There is a need to somehow manage / exploit the explosion of information appearing on multiple WWW sites with very variable standards of data quality and currency - and of course there is the need to know such data sources exist. This has the major aspects of: (a) data quality (b) query quality (c) answer quality (d) integration of heterogeneous sources Let us consider each briefly in turn. 1.1.1 Data Quality Data quality can be improved by better data collection facilities (including help and explanation with examples) and better validation controlled by constraints, with automated conversions of unit values if required or necessary. 1.1.2 Query Quality Query quality can be improved not only by classical query optimisation using knowledge about the database size and structure, but also by assisting the user to formulate the query best to meet the req