Re: Date's First Great Blunder
Date: Mon, 19 Apr 2004 09:42:47 -0500
"Laconic2" <laconic2_at_comcast.net> wrote in message
> > I care naught for code size. In the 80's when I had COBOL programmers
> > working for me (and was one myself),
> If you managed COBOL programmers in the 1980s, but never heard of the
> hierarchical or network data models, except as "marketing for the
> model", then you have led a sheltered existence, indeed.
> Ever hear of IMS? It was built on the hierarchical model of data. Ever
> hear of IDMS (not IDMS/R)? It was built on the network model of data.
> These are just two examples. Any COBOL shop that had some exposure to the
> prerelational COBOL/DBMS world had some exposure to one of these models of
Perhaps you misunderstood me. I have worked with IMS extensively and have touched IDMS. I don't think that there was anyone in the building of IMS that called IMS a "hierarchical" database, but I could be wrong. It is my impression that the terms "network database" and "hierarchical database" were prepared by relational database theorists in describing how their database implementations differed from those that were out there already. If the IDMS folks, for example, set out to create something they called a "network database" then I'm interested in any historical information on that. I read a bunch of database history a few months ago and it was my impression that these terms were coined by the relational database "industry" somewhere along the line.
> As far as comparisons between data models go, Codd's work in the early
> 1970's was proposing a new data model. To propose a new data model,
> comparing it to existing data models, would have been irresponsible. Codd
> made the comparison. If you want to dismiss Codd's work as "marketing
> hype", well, who am I to argue?
I most certain do not do that! However, when I read in textbook after textbook something that could be summarized as "there are three possibilities -- network, hierarchical, and relational and relational is obviously better" then I know there is some thread of marketing going on. Of course now they add that there are also OO databases, perhaps XML dbs and they might mention a few others ("semantic web" etc). But the entire wealth of knowledge related to persisting data in 1950-1990 outside of RDBMS's is typically narrowed down to IMS as hierarchical and IDMS as network databases, prior to being dismissed entirely by the text book.
> As far as "an RDBMS has never been built", I agree with you. That's not a
> useful position to take. No one has ever built a triangle either. But
> kindergarten teacher had an approximate triangle that she held up in
> and said "This is a triangle". Close enough.
Great analogy! --dawn Received on Mon Apr 19 2004 - 16:42:47 CEST