This is a book on database management that is based on an earlier book by the same authors, Foundation for Future Database Systems: The Third Manifesto. It can be seen as an abstract blueprint for the design of a DBMS and the language interface to such a DBMS. In particular, it serves as a basis for a model of type inheritance. This book is essential reading for database professionals.

This book is a proposal for the future direction of data and database management systems (DBMSs). It provides a precise, formal definition of an abstract model of data, to be considered as a foundation for the design of a DBMS and a database language.

The proposed foundation represents an evolutionary step, not a revolutionary one; it builds on Ted Codd's relational model of data and on the research that sprang from Codd's work. It also incorporates a precise and comprehensive specification for a method of defining data types, including a comprehensive model of type inheritance based on specialization by constraint (as opposed to the "extension" method of subtyping found in object-oriented languages). Thus, it not only redefines the relational model in modern terms and clarifies it where clarification seemed necessary, but also addresses the orthogonal issue of the data types on whose existence the relational model depends. It is therefore offered as a firm foundation for the DBMSs of the future and is essential reading for database students and professionals alike.