D (data language specification)

D is a set of requirements for what Christopher J. Date and Hugh Darwen believe a relational database query language ought to be like. It is proposed in their book The Third Manifesto.

Overview

D by itself is an abstract language specification. It does not specify language syntax. Instead, it specifies desirable and undesirable language characteristics in terms of prescriptions and proscriptions. Thus, D is not a language but a family of both implemented and future languages. A "valid D" must have a certain set of features, and exclude a different set of features which Date and Darwen consider unwise. A valid D may have additional features which are outside the scope of relational databases.

Tutorial D

Tutorial D is a specific D which is defined and used for illustration in The Third Manifesto. Implementations of D need not have the same syntax as Tutorial D. The purpose of Tutorial D is both educational and to show what a D might be like. Rel is an implementation of Tutorial D.

Implementations

D’s first implementation is D4, written in C#. D4 is the flagship language of Alphora's Dataphor. Others include Rel (see above), Opus, Duro, and Dee.

References

• Christopher J. Date and Hugh Darwen. (1998) Foundations for Future Databases: The Third Manifesto.
• 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 edition ed.). Reading, MA: Addison-Wesley. xxi, 496. ISBN 0-201-30978-5. OCLC 38431501. LCCN 98-10364 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 edition ed.). Reading, MA: Addison-Wesley Professional. xxiii, 547. ISBN 0-201-70928-7. OCLC 43662285. LCCN 00-35527 LCC QA76.9.D3 D3683 2000. 

External links

• Tutorial D explained
• Tutorial D's grammar in alphabetical order
• ALGEBRA, a recursive name that means A Logical Genesis Explains Basic Relational ALGEBRA.
• The Third Manifesto
• Alphora
• Rel - An Implementation of Date and Darwen's Tutorial D database language.
• Duro - a relational database management system
• Dee - makes Python relational