Date and Darwen wrote:This book consists of a collection of exploratory essays on database management--more specifically, on issues arising from and related to The Third Manifesto, which is a proposal by the authors for a foundation for data and database management systems (DBMSs). Like Codd's original papers on the relational model, The Third Manifesto--"the Manifesto" for short--can be seen as a blueprint for the design of a DBMS. It consists in essence of a rigorous set of principles, stated in the form of a series of prescriptions and proscriptions, that we require adherence to on the part of a hypothetical database programming language that we call D. We've described those prescriptions and proscriptions in detail in our book Databases, Types, and the Relational Model: The Third Manifesto, 3rd edition (Addison-Wesley, 2006)--referred to throughout the present book as "the Manifesto book" for short. Note: More information relating to the Manifesto can be found on the website www.thethirdmanifesto.com. In particular, information can be found on that website regarding a number of experimental--and, in at least one case, commercial--implementations of the Manifesto ideas (see later in this preface). 

Prerequisites

Our target audience is database professionals. Thus, we assume you're somewhat familiar with both the relational model and the SQL language (though certain relational and/or SQL concepts are reviewed briefly here and there--basically wherever we felt such explanations might be helpful). Prior familiarity with The Third Manifesto would also be advantageous. 

• The book website