The fourth international conference on Extending Data BaseTechnology was held in Cambridge, UK, in March 1994. Thebiannual EDBT has established itself as the premier Europeandatabase conference. It provides an international forum forthe presentation of new extensions to database technologythrough research, development, and application. This volumecontains the scientific papers of the conference. Followinginvited papers by C. M. Stone and A. Herbert, it contains 31papers grouped into sections on object views, intelligentuser interface, distributed information servers, transactionmanagement, information systems design and evolution,semantics of extended data models,accessing new media, joinalgorithms, query optimization, and multimedia databases.