Re: Hierarchical Model and its Relevance in the Relational Model

Jan

> On Sunday, 1 February 2015 05:07:34 UTC+11, Jan Hidders wrote:

No worries. Take your time. I am happy to wait for the long, considered response. I would like the thread to progress to completion, with considered responses all the way through.

> 1. You don't need my permission to discuss one of my papers here, but if you would like my explicit permission, then you have it now.

I know that. It was a matter of courtesy. Some people may not appreciate having their papers discussed in open forum.

> I would btw. be very curious to know what conclusions your client would think he or she could draw from them.

Since I have already given you a synopsis, a short chronology, I am not sure what you mean. Would you like a more complete one ?

Further, if we are going to work through the main issue in the paper, the conclusions (now) would be detailed (as opposed to the conclusions drawn by hundreds of others, previously, which are incorrect).

I suspect you and I are not on the same page on this one. So let me clarify, and ask for a clarification.

Now in this thread you have stated:

> > But most /now/ understand the relevance of data independence.

(My emphasis.)

To which I replied:

> I suppose I have to trust that you mean that in the fullness of the data integrity as prescribed in the RM.

Which you have not confirmed or denied. Which means, I still do not know the /extent/ to which you understand "data independence", and how it is administered.

So the clarification begs. The paper is Database Programming Languages, 1995. Are you aware:

1. That, on the face of it, your statement above, contradicts, or let's say unofficially retracts, the main thrust, the solution given, in your 1995 paper ? __ (which is why I stated "... the papers have not been retracted, all we have is a statement from the author in an unrelated post on c_d_t stating that "most /now/ understand the relevance of data independence.")

Or, do you stand, on that paper, now ?

2. Of the Architectural Principle, established as science in our field, that Data must be separated from Process ? __ (And it follows that there are separate and different methods for Analysing & Designing the two, etc, etc.) __ It is clearly established in the industry, that implementers are specialists in either the /Data Space/ xor the /Program Space/ (those who cover both are few, and exceptional).

3. That [2] existed, as science, before Codd, 1970, the RM ? __ (That it has been furthered ever since then, and rendered for whatever context one uses (eg. a RDB; an awk script). That it (as with everything in science) has only gotten stronger as an Architectural Principle, and applicable in more contexts.

4. That in his paper, the RM, in 1970, Codd gave specific /further/ prescriptions and prohibitions re "data independence", without having to explain what "data independence" meant, because it was well-known ? __ Which resulted in implementation of those concepts in the commercial RDBMS platforms, as well as in the implementations of RBDs.

5. The result being, that 100% of all controls upon data should be deployed in the RDB ? __ (As I am sure you know, DKNF alludes to this. We implement a much fuller form, as standard practice.)

6. The corollary being, that controls on the data should not be deployed in the /Program Space/. Eg. OO Objects or classifiers ? __ And if it is deployed there, (a) it will never be adequate, or (b) as complete, as a deployement in the /Data Space/. Something that has been painfully proved in millions of OO-centric implementations.

Very short answers, please.

> 2. An important point of disagreement between us seems to be what is and what is not part of The Relational Model or how a certain group of people or individuals interpreted it in the past.

Yes and no. I am uncomfortable with the way that is stated. AFAIC, I don't have a disagreement with you (yet), which is why I have taken the approach that I have.

It is only by interacting with people here, mathematicians, theorists, others, that I have been able to determine the problems in this industry, and the causes. As per my OP, I charge that many of the mathematicians and theorists in this space write articles and posts re the RM, and they do so from a position of authority. What I am finding out, to my horror, sadly, is that they actually know sweet fanny adams about the RM. Which means they have no business theorising about it, and their claim to authority is false. I have singled you and James out because you have (a) made offending posts such as I describe, and (b) at the same time exhibit small knowledge of the RM. You represent the whole group, and you are direct enough that I can draw the problem out, confirm it, and thus address a massive hindrance in my profession.

• Aside --

BTW, note from all this, it is not a personal or personality issue re you or James. I am very grateful that I can interact with you and James, that you two are honest enough, for me to chase this down, and to identify the exact causes of the problem. As I have clearly stated, you two are category [2], victims, you are not the cause category [3]. I can only determine and confirm the cause, through you. I need evidence, specifics, such as in your paper, who, which mentor, gave you that direction, etc. Again, this is not about trashing your paper in a public forum, this is about identifying the specific errors, and under whose direction you made them.

Eg. I took it up first with the Date, Darwen, and Fagin, and they would not (could not ?) answer anything directly. They cannot read or understand data models; technical English; etc. So they are proved to be even less scientific and less capable than the posters here, working in the Dark Ages. I endured three years at TTM, so I know their game well. The suggestion that it has anything to do with the RM is false. I didn't drink the Kool-Aid, so I did not fit in.

• End Aside --

What is and what is not part of the RM, is not an arguable issue. Simply read it, and determine that. There may well be related issues such as, a good standards-compliant implementer takes more out of the RM, gets more direction from it, than a poor one, but that is a separate point. What is in or out is simple.

There is an issue with some theorists, mathematicians (whom I have categorised as [2] Ignorant), in that they invent things (propose new contemplation, representations, and perspectives), that already exist in our science, or more specifically, in the RM. I am addressing that as an important but secondary issue, because that activity is a stupid and avoidable waste of time and money. This industry is very poorly served in terms of theoreticians, there has be zero advancement since Codd (all advances have been by scientists who are employed by the vendors, sans papers published, and to a lesser degree by faithful disciples like me). Those researchers should instead, study the sciences involved; study the RM; and then extend, advance it.

> To be honest, although I have opinions on these issues, I find such discussions unscientific and without any merit, even if it is about how Codd himself meant his model to be understood. It is akin to the argument by authority, which is a very weak type of argument.

Per details above, I do not expect that type of argument.

We do need to take Codd as the authority. Otherwise we can pack our bags and go home.

> What matters is, which objective arguments were put forward to support that interpretation and what the evidence for its merit was. Which interpretation leads to the most effective DBMSs [, RDBs] and what scientific evidence is there for this.

Note my insertion.

Yes, all very good points. But I think even that /could/ be avoided, or let's say, easily stated and closed: the /commercial/ vendors have already done that work; the high-end implementers implement it. Something that the theoreticians do not seem to be able to comprehend. they are about thirty years behind the industry that they theorise for. You will of course, have to accept evidenced reality as scientific evidence, not papers by theoreticians who have already established themselves as un-scientific. Mathematical proofs alone are pure garbage.

> I'd prefer it if we could focus on that in future exchanges.

Sure. As long as we keep progressing on the main issues, and close them.

> 3. I'm not a mathematician, so would like to ask you to not refer to me in that way. I use math in my research. I have real mathematicians as my coauthors. But I do not hold a PhD or MSc in mathematics, so cannot really make that claim.

My apologies. You sure write a lot of papers in the space. Do you then consider yourself a theoretician in this space ?

Actually, if you excised the mathematical proofs from your papers, it would increase their credibility. Because the mathematical proofs have been proven false in the course of time, or were false from the beginning due to their contradicting other sciences.

Cheers
Derek Received on Sun Feb 01 2015 - 06:33:38 CET