Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!cs.utexas.edu!uunet!ncrlnk!ciss!dbruck From: dbruck@ciss.Dayton.NCR.COM (Don Bruck@ciss.Dayton.NCR.COM) Newsgroups: comp.databases Subject: Re: Relational Model (Was Re: Oracle: Previous Record) Summary: Processes are NOT data Keywords: relational empirical support Message-ID: <798@ciss.Dayton.NCR.COM> Date: 21 Jul 89 17:30:07 GMT References: <18886@sequent.UUCP> Reply-To: dbruck@ciss.UUCP (Don Bruck@ciss.Dayton.NCR.COM) Distribution: usa Organization: NCR Corp. Network Application Services Lines: 38 In article <18886@sequent.UUCP> normb@sequent.UUCP (Norm Browne) writes: >In article bg0l+@andrew.cmu.edu (Bruce E. Golightly) writes: >>There are indeed times when you can't think in terms of the relational >>model. Sometimes the users insist that they want what they want, and you >>can't do it without breaking the model. We had to write an application > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ >>to do this kind of thing a while back. >> > >[At the risk of being labeled a heretic in the contemporary dbms world. :-)] > > Does it strike anyone else that the above kind of > statement indicates that the relational model is > not a very accurate depiction of the real world? > <<< deleted stuff >>> > >BTW- I am not attacking relational per se (so cool the flamethrowers :-)), >it just seems that the theory is lacking some empirical support. > I wish to agree with both writers. The relational model implies that the world is un-ordered, that A is not necessarily the the predecessor to B, as in the word BAD. The relational model therefore does not support "PREVIOUS" and I understand the reasons. What bothers me is that some companies use this excuse and then support other things not in the relational model such as "NEXT" and indices. A solution to this is to realize that DATA and PROCESS are significantly different. Data is random, process is ordered. Store data randomly and allow the processes to order it as needed for the process. In this way of looking at the problem INDEXing, "NEXT", and "PREVIOUS" are part of the process. The INDEX is a tool of the process's need for "NEXT" "PREVIOUS" "LAST" "FIRST" and all of the other ordering functions needed. ------------------------------------------------------------------------------- Don Bruck My opinions are my own and my wife does know I have them.