A major theme of the manifesto is to explain how the inadequacies of existing relational database management systems are not shortcomings of the relational database model per se, but rather, of implementation decisions in those systems, and of the SQL query language that most of these systems use.
The manifesto describes an alternative to SQL, named D. D is a specification of desirable characteristics of a database language, rather than a specific syntax or grammar. As such, it describes a family of languages rather than any particular language. However, as an example, a particular member of the hypothetical D "family" called Tutorial D is described in detail, including significant portions of its grammar.
Several partial implementations of D exist, including:
Alphora Dataphor, an open source product which implements the language D4 atop SQL databases.
Date, C. J. (August 1998). "Preview of The Third Manifesto". Database Programming & Design. San Francisco, CA: Miller Freeman Publications. 11 (8): 67. ISSN 0895-4518. OCLC 89297479. Retrieved 2007-06-18.
Date, C. J.; Darwen, Hugh (1998). Foundation for object/relational databases: the third manifesto: a detailed study of the impact of objects and type theory on the relational model of data including a comprehensive proposal for type inheritance (1st ed.). Reading, MA: Addison-Wesley. xxi, 496. ISBN 0-201-30978-5. LCCN 98010364. OCLC 38431501. LCC QA76.9.D3 D15994 1998.
Date, C. J.; Darwen, Hugh (2000). Foundation for future database systems: the third manifesto: a detailed study of the impact of type theory on the relational model of data, including a comprehensive model of type inheritance (2nd ed.). Reading, MA: Addison-Wesley Professional. xxiii, 547. ISBN 0-201-70928-7. LCCN 00035527. OCLC 43662285. LCC QA76.9.D3 D3683 2000.