An authoritative resource for reader's interested in gaining insight into and understanding of the principles of database systems.This exciting revision continues to provide a solid grounding in the foundations of database technology and to provide some ideas as to how the field is likely to develop in the future.The material is organized into six major parts. Part I provides a broad introduction to the concepts of database systems in general and relational systems in particular. Part II consists of a careful description of the relational model, which is the theoretical foundation for the database field as a whole. Part III discusses the general theory of database design. Part IV is concerned with transaction management. Part V shows how relational concepts are relevant to a variety of further aspects of database technologysecurity, distributed databases, temporal data, decision support, and so on. Finally, Part VI describes the impact of object technology on database systems.