The competitive edge of many companies and public trust in government institutions can often depend on the security of the information now held in databases. Breaches of that security are a highly topical issue for both designers and users of database systems. This book provides an authoritative account of security issues in database systems, and shows how current commercial or future systems may be designed to ensure both integrity and confidentiality. It gives a full account of alternative security models and protection measures, including those for new-generation systems like distributed, frame-based and object-oriented databases. The book can serve as a text for advanced courses on DB Security.