Integrity Maintenance in Advanced Data Bases Ulrich Schiel Universidade Federal da Paraíba Departamento de Sistemas e Computação C.P. 10106 / 58109-970 Campina Grande - PB e-mail: ulrich@dsc.ufpb.br INTRODUCTION The use of databases for advanced applications is a rapidly growing and changing field, due to the continuous incorporation of new technologies and media in current systems. Whereas in the near past Database Management Systems (DBMS) mainly use to store and manage tabular data, now they need to model complex structured objects, multimedia data, semi-structured and unstructured documents. Each of these improvements has its own semantics and complexity. In order to allow an adequate description of database applications, data models are used to describe the conceptual schema of the database. If new categories of applications need to be incorporated or created, and the data model does not fits well with these applications, the model itself must be expanded. The semantics of the new constructs must be defined and the integrity of objects in the new constructs must be guaranteed. Since a DBMS is in general not expandable, except for future versions of the same product, there are two alternatives. Move the whole application to another system that is capable to adequately process the new structures, or develop specific routines, probably with its own storage systems, in order to incorporate the new application. Clearly both solutions are unsatisfactory. The first solution is only applicable if there exists a DBMS that considers the new structures. Even if it exists, moving to the new environment means reimplementation of the application, and this is very traumatic and demands a lot of time and money. The other solution, to expand existing applications by special modules is more straightforward, but creates an unbalanced heterogeneous system, combining a databases with a file system. This generates problems of integration and does not allow a unified view of the data of the application. Despite actual existing DBMS consider many modern database concepts, such as object- orientation and triggers, there are a lot of applications needing more. Concepts of temporal databases, geographic databases, hypertext (Web-) databases are not well attended.