Any attempts to define an instance of Date/Darwen's 'D' language (and implement it ?)

In the book 'Foundation for Future Database Systems: The Third Manifesto'[1], Date and Darwen put forward a detailed proposal for the future development of database technology, and describe a data definition/query language they call 'D', intended to replace/complement SQL. In particular, their proposal has many of the perceived strengths of object databases while remaining firmly relational with all the benefits that entails (solid theoretical background, ad-hoc query support, more amenable to optimization, enforcement of integerity.. etc).

I'm surprised I can't seem to find any attempts by anyone to design the language, or for that matter, to implement a DBMS based on the principles laid out in the book. At the least, I'd imagine it could make a good subject for a PhD thesis.

Does anyone know of any references to any projects along these lines?

Cheers,
Kieran

[1]
http://www.amazon.com/exec/obidos/ASIN/0201709287/qid=1009062224/sr=1-1/ref=sr_1_0_1/002-6078174-5331262

PS: For those unfamiliar with C.J. Date's work, I'd recommend taking a look at http://www.firstsql.com/dbdebunk/. Received on Sat Dec 22 2001 - 17:42:26 CST