Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!rutgers!apple!usc!cs.utexas.edu!uunet!zephyr.ens.tek.com!tektronix!sequent!normb From: normb@sequent.UUCP (Norm Browne) Newsgroups: comp.databases Subject: Re: Relational Model Keywords: relational empirical support Message-ID: <19101@sequent.UUCP> Date: 24 Jul 89 15:46:36 GMT References: <18886@sequent.UUCP> <606@daitc.daitc.mil> <220@intek01.UUCP> Reply-To: normb@sequent.UUCP (Norm Browne) Organization: CARLINOR - CA Refugees Living IN OR Lines: 42 In article <606@daitc.daitc.mil> jkrueger@daitc.daitc.mil (Jonathan Krueger) writes: >In article <18886@sequent.UUCP>, normb@sequent (Norm Browne) writes: >>I could find no substantiation >>that the relational model _really_ represented real world applications. > > [long digression on maps to the make the point that a model *isn't* > the real world] >-- and >From: mark@intek01.UUCP (Mark McWiggins) >Message-ID: <220@intek01.UUCP> > >The empirical support is everywhere: scads of working applications based >on the relational model that deal more-or-less appropriately with >real-world stuff. Why bother with any other proof? I concede the obvious above points on maps (models) as abstractions and lots of working applications. Now, back to the [basically academic] point I was trying to get at... One of the relational model's [supposed] major advantages is that it has a THEORETICAL underpinning (mathematical set theory). This is why it is ``superior'' to the Codasyl or hierarchical models. Does set theory really reflect the real world?[1] Is it more intuitive? What I could not find was substantiation of this (if the theory is `valid' there should be supporting empirical evidence, otherwise it's like economics :-) ). I have used DBMSs based on all three models and each had unique functionality, strengths, and weaknesses, so this is really a question about theory. BTW- answers that include ``thinking relationally'' do not qualify. In a separate thread was a discussion of normalization, E-R and relational. Normalization and E-R can be applied to network and hierarchical DBs so they also do not differentiate relational DBs. [1] Let me give a specific example. Set theory dictates that order is irrelevant (i.e. unordered sets). What real world application looks at data [usefully] as unordered? The first thing that is added is an index which is *NOT* part of set theory! ----Norm