Integrity Issues in the Web: Beyond Distributed Databases

INTRODUCTION Issues related to integrity in databases and distributed databases have been introduced in previous chapters. Therefore, the integrity problem in databases and how it can be managed in several data models (relational, active, temporal, geographical, and object-relational databases) are well known to the reader. The focus of this chapter is on introducing a new paradigm: The Web as the database, and its implications regarding integrity, i.e., the progressive adaptation of database techniques to Web usage. We consider that this will be done in a quite similar way to the evolution from integrated file management systems to database management systems. In any case, this will be a much more difficult goal and quite a lot of work is still to be done. The special features of the Web make things which are necessary on a database system just optional in this environment. On the other hand, some other things which are usually considered as essential parts of any database, are now disassembled into its building blocks and used as needed (Silberschatz & Zdonik, 1996; Bernstein et al., 1998). At first glance, the Web is a huge repository of information without any structure whatsoever. Nowadays, this is changing quickly. The consolidation of the Extensible Markup Language (XML,1998) as a new standard adopted