Re: Requirements for update languages?
Date: Thu, 14 Nov 2002 14:40:52 +0200
> However, not everything is perfect in the relation world. The next
> exercise would be trying defining aggregate in the *pure* relational
> terms. A recent posting shows how unnatural defining simple
> ariphmetics facts in the relational terms is:
Quote from same article (by Date)
and grouping have been part of the algebra ever since the early 1970s (and possibly earlier); that seems classical enough to me! (In case you're interested, the reference I have in mind here is the paper by Patrick Hall, Peter Hitchcook, and Stephen Todd entitled "An Algebra of Relations for Machine Computation", which appeared in the Conference Record of the 2nd ACM Symposium on Principles of Programming Languages, Palo Alto, CA., January 1973. See also Stephen Todd’s paper "The Peterlee Relational Test Vehicle – A System Overview", IBM System Journal 15, No. 4, 1976.)
I have not read these articles (I wonder if they are available on line), so I don't have an opinion on wheter these answer the question or not. Maybe somebody does?
Lauri Pietarinen Received on Thu Nov 14 2002 - 13:40:52 CET