This book provides a comprehensive yet concise coverage of the concepts and technology of database systems and their evolution into knowledge-bases. The traditional material on database systems at senior undergraduate level is covered. An understanding of concepts is emphasized avoiding extremes in formalism or detail.Rather than be restricted to a single example used over an entire book, a variety of examples are used. These enable the reader to understand the basic abstractions which underlie description of many practical situations.A major portion of the book concerns database system technology with focus on the relational model. Various topics are discussed in detail, preparing the ground for more advanced work.