Re: What is a "data sublanguage"
Date: Tue, 18 Dec 2007 17:35:46 -0400
David Cressey wrote:
> It's time for me to ask another dumb question.
> The term "data sublanguage" appears in Codd's 1970 paper. I kind of glossed
> over it when I first read it, figuring that my intuitive grasp was close
> enough. Now I'm wondering whether I really know what "data sublanguage"
> means, at all.
> What is a "data sublanguage"? What is the difference between a
> "sublanguage" and a "language"? Can a programming language embed a data
> sublanguage as a subset of the syntax and semantics of the programming
> language? Does the data sublanguage Codd was referring to span all the
> syntax and semantics of the relational data model?
> Did SQL take the place of the data sublanguage Codd was suggesting should be
> built? Have Date & Darwen or others created a relational data sublanguage?
A sublanguage is simply a proper subset of a language devoted to some identified task. SQL has DML and DDL sublanguages. Some languages support embedding SQL as a sublanguage through a pre-processor etc. Received on Tue Dec 18 2007 - 22:35:46 CET