D (data language specification)

From Wikipedia, the free encyclopedia

D is a set of requirements proposed by Christopher J. Date and Hugh Darwen in their book The Third Manifesto for what they believe a relational database query language ought to be like; D is not a language itself.

Contents

[edit] Overview

D, by itself, refers to a set of requirements proposed by Date and Darwen for what they believe a relational language ought to be like. Tutorial D is an abstract instantiation of D which is described and used in The Third Manifesto. It should be noted that it is not required for instantiations of D to have the same syntax as Tutorial D; just that 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.

Note that this D is distinct from the D language, which is a general purpose programming language.

[edit] Tutorial D

Tutorial D is an abstract instantiation of D, described and used in The Third Manifesto. The purpose of Tutorial D is to show what a D might be like. Its purpose is educational.

[edit] Industrial D

While Tutorial D is an academic language, any relatively faithful implementation of D meant to be used in the industry is called an Industrial D.

[edit] Implementations

D’s first implementation is D4, written in C#. D4 is the flagship language of Alphora's Dataphor. Others include Rel, Opus, Duro, and Dee. All would be considered "Industrial D"s.



[edit] See also

[edit] Implementations

[edit] Authors

[edit] External links

[edit] References