Re: 4 the Faq: Strengths and Weaknesses of Data Models

From: Costin Cozianu <c_cozianu_at_hotmail.com>
Date: Wed, 13 Oct 2004 15:04:00 -0700
Message-ID: <2t5n2uF1sgejuU1_at_uni-berlin.de>


Kenneth Downs wrote:

> It seems to be taken for granted by the majority in this ng that the RDM is
> superior to the hierarchical and network data models. I am in that
> majority, but I realize it is probably for me more a matter of faith than
> proof.
>
> So the question is: why did RDM win the database wars? Was it really on
> strengths, or was it, shudder to think, just one of those trends that IT
> goes through?
>
> What is normally stated in the group is that RDM has a mathematical basis
> that gives us a strategy for correctness, which Hierarchical and Network
> did not. Yet somebody in this ng mentioned a few days ago that those
> models were given a more rigorous footing later on. Could the hierarchical
> model now be just as thorough, except that RDM already won?
>

The fact that something has a mathematical basis or a mathematical formalism, says nothing about the value and the adequacy.

Let me tell you a secret: everything that fits inside a computer is a mathematical object. And regardless of uninformed claims to the contrary , you can have a mathematical model behind everything: OO, relational model, SQL, IMS, Cobol, X86 machine code, XML -- any programming concept of all.As a matter of fact there are lots of mathematical models, even several alternative for the same target.

The greatest problem though is how adequate is some mathematical model for the chief purpose in programming practice : managing complexity and achieving correctness. Most mathematical models are complicated, complex, unintuitive, not easy to make derivations with, ugly (as per Dijkstra: *beauty is our business* ) and suffers quite a lot of undesirable properties as mathematical models nevertheless.

Looking from this point of view, the classical relational model it is a piece of jewelry.

Costin Received on Thu Oct 14 2004 - 00:04:00 CEST

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