This volume constitutes the proceedings of the 4thInternational Conference on Database and Expert SystemsApplications (DEXA), held in Prague, Czech Republic, inSeptember 1993.Traditionally the objective of the DEXA conferences is toserve as an international forum for the discussion andexchange of research results and practical experinece amongtheoreticians and professionals working in the field ofdatabase and artificial intelligence technologies. Despitethe fact that in the conference title the applicationsaspect is mentioned explicitly, the theoretical and thepractical points of view in the field are well-balanced inthe program of DEXA'93. The growing importance of theconference series is outlined by the remarkably high numberof 269 submissions and by the support given by renownorganizations. DEXA'93 is held for the first time outsidethe former GDR in an East-European country, and isessentially contributing to the advancement of the East-Westscientific cooperation in the field of database and AIsystems.This proceedings contains the 78 contributed paperscarefully selected by an international program committeewith thesupport of a high number of subreferees. The volumeis organized in sectionson data models, distributeddatabases, advanced database aspects, database optimizationand performance evaluation, spatial and geographicdatabases, expert systems and knowledge engineering, legalsystems, other database and artificial intelligenceapplications, software engineering, and hypertext/hypermediaand user interfaces.