Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!ncar!ames!amdahl!pacbell!rtech!davek
From: davek@rtech.rtech.com (Dave Kellogg)
Newsgroups: comp.databases
Subject: Re: Informix an RDBMS?
Message-ID: <2739@rtech.rtech.com>
Date: 20 Mar 89 15:38:08 GMT
References: <217@zeek.UUCP>
Reply-To: davek@rtech.UUCP (Dave Kellogg)
Distribution: usa
Organization: Relational Technology Inc, Alameda CA
Lines: 40

In article <217@zeek.UUCP> larry@zeek.UUCP (Larry Podmolik) writes:
> He then said Informix had "honorary mention" in that
>group because it was a relational interface built on top of a non-
>relational (C-ISAM) engine.  (BTW, neither Unify nor Ingres was
>mentioned at all.)
>
>I guess I don't understand what a truly "relational engine" is in that
>sense (i.e.  why Informix doesn't qualify).  And what about Ingres
>and Unify?
>
>Any enlightenment appreciated.
>

I'm not sure what they guy is talking about and would appreciate a solid
reference to the article so I can check it out.

Fundamentally, the guy seems off the mark.  (Especially since he works at
Codd and Date because his own boss defines things differently...) The 
bottom line is that relational is as relational appears.  At the lowest
level of abstraction it's all 1's and 0's on some disk anyway.  The relational
model is concerned at how the data APPEARS to its users.  My guess is you
could make a relational "engine" on top of a bunch of file clerks and manila
folders if the clerks PRESENTED the data relationally to its end users.

Quoting Date (Guide to DB2):

	... the relational model is a way of looking at data--
	that is, a prescription for how to represent data and how
	to manipulate that representation...

Thus, in my book, to determine whether a DBMS is relational or not you
don't look at how it stores things or how it internally works.  Rather,
you look at the way the data is presented to you and the query language
and its operators.

David Kellogg
Relational Technology New York

As usual, these thoughts are mine (or Date's) and not necessarily those of
my employer.