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devel / comp.databases.theory / Re: "Theoreticians” are Clueless about Relational Data Modelling, Teach Anti-Relational Muddling

SubjectAuthor
* "Theoreticians” are Clueless about Relational DataDerek Ignatius Asirvadem
`* Re: "Theoreticians” are Clueless aboutNicola
 +* Re: "Theoreticians” are Clueless aboutNicola
 |`* Re: "Theoreticians” are Clueless about RelationalDerek Ignatius Asirvadem
 | `* Re: "Theoreticians” are Clueless aboutNicola
 |  `* Re: "Theoreticians” are Clueless about RelationalDerek Ignatius Asirvadem
 |   `* Re: "Theoreticians” are Clueless aboutNicola
 |    +* Re: "Theoreticians” are Clueless about RelationalDerek Ignatius Asirvadem
 |    |+- Re: "Theoreticians” are Clueless aboutNicola
 |    |`* Re: "Theoreticians” are Clueless aboutNicola
 |    | +- Re: "Theoreticians” are Clueless about RelationalDerek Ignatius Asirvadem
 |    | `* Re: "Theoreticians” are Clueless about RelationalDerek Ignatius Asirvadem
 |    |  `* Re: "Theoreticians” are Clueless aboutNicola
 |    |   `* Re: "Theoreticians” are Clueless aboutNicola
 |    |    `* Re: "Theoreticians” are Clueless about RelationalDerek Ignatius Asirvadem
 |    |     +- Re: "Theoreticians” are Clueless about RelationalDerek Ignatius Asirvadem
 |    |     `* Re: "Theoreticians” are Clueless aboutNicola
 |    |      +- Re: "Theoreticians” are Clueless aboutNicola
 |    |      `* Re: "Theoreticians” are Clueless about RelationalDerek Ignatius Asirvadem
 |    |       `* Re: "Theoreticians” are Clueless aboutNicola
 |    |        `* Re: "Theoreticians” are Clueless about Relational Data Modelling, Teach Anti-RelDerek Ignatius Asirvadem
 |    |         +- Re: "Theoreticians” are Clueless about RelationalDerek Ignatius Asirvadem
 |    |         `* Re: "Theoreticians” are Clueless aboutNicola
 |    |          `* Re: "Theoreticians” are Clueless about RelationalDerek Ignatius Asirvadem
 |    |           +- Re: "Theoreticians” are Clueless aboutNicola
 |    |           `* Re: "Theoreticians” are Clueless about RelationalDerek Ignatius Asirvadem
 |    |            +- Re: "Theoreticians” are Clueless about RelationalDerek Ignatius Asirvadem
 |    |            +- Re: "Theoreticians” are Clueless about Relational Data Modelling, Teach Anti-RelDerek Ignatius Asirvadem
 |    |            `* Re: "Theoreticians” are Clueless about RelationalDerek Ignatius Asirvadem
 |    |             +* Re: "Theoreticians” are Clueless about RelationalDerek Ignatius Asirvadem
 |    |             |`* Re: "Theoreticians” are Clueless about RelationalDerek Ignatius Asirvadem
 |    |             | `* Re: "Theoreticians” are Clueless aboutLP
 |    |             |  +* Re: "Theoreticians” are Clueless about RelationalDerek Ignatius Asirvadem
 |    |             |  |`* Re: "Theoreticians” are Clueless aboutLP
 |    |             |  | +- Re: "Theoreticians” are Clueless about RelationalDerek Ignatius Asirvadem
 |    |             |  | +- Re: "Theoreticians” are Clueless about RelationalDerek Ignatius Asirvadem
 |    |             |  | +- Re: "Theoreticians” are Clueless about RelationalDerek Ignatius Asirvadem
 |    |             |  | `- Re: "Theoreticians” are Clueless about RelationalDerek Ignatius Asirvadem
 |    |             |  `- Re: "Theoreticians” are Clueless about RelationalDerek Ignatius Asirvadem
 |    |             +- Re: "Theoreticians” are Clueless about RelationalDerek Ignatius Asirvadem
 |    |             `* Re: "Theoreticians” are Clueless about RelationalDerek Ignatius Asirvadem
 |    |              +- Re: "Theoreticians” are Clueless aboutLP
 |    |              `* Re: "Theoreticians” are Clueless about Relational Data Modelling, Teach Anti-RelDerek Ignatius Asirvadem
 |    |               `- Re: "Theoreticians” are Clueless aboutLP
 |    `* Re: "Theoreticians” are Clueless about RelationalDerek Ignatius Asirvadem
 |     `- Re: "Theoreticians” are Clueless aboutNicola Vitacolonna
 `* Re: "Theoreticians” are Clueless about RelationalDerek Ignatius Asirvadem
  +* Re: "Theoreticians” are Clueless aboutNicola
  |`- Re: "Theoreticians” are Clueless about RelationalDerek Ignatius Asirvadem
  `* Re: "Theoreticians” are Clueless aboutNicola
   +* Re: "Theoreticians” are Clueless about RelationalDerek Ignatius Asirvadem
   |`- Re: "Theoreticians” are Clueless aboutNicola
   `- Re: "Theoreticians” are Clueless about RelationalDerek Ignatius Asirvadem

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"Theoreticians” are Clueless about Relational Data Modelling, Teach Anti-Relational Muddling

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Subject: "Theoreticians”_are_Clueless_about_Relational_Data
_Modelling,_Teach_Anti-Relational_Muddling
From: derek.as...@gmail.com (Derek Ignatius Asirvadem)
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 by: Derek Ignatius Asirv - Mon, 29 Mar 2021 07:59 UTC

Introduction

When it came out in 1970, the Relational Model (Codd, not the pretenders) made a paradigm shift in all areas of perceiving data (examination; data modelling; storage and retrieval; programming). Codd had an uphill battle against the established academics because they could not understand it, and against a few of the DBMS vendors, because they were interested in protecting their established products. It took about ten years to overcome those obstacles, and then it took off. IBM had an internal product that progressed through the 1970’s, eventually becoming SQL, and the market begged them to release the definition, so that it could be made a Standard, such that other vendors could provide platforms.

For those who are not old enough to remember, we had perfectly good DBMS in those days, and fairly intense design methods, first for data in general and second for the implementation in our particular DBMS. It just was not a model, in the sense that the /RM/ is a genuine model, defined mathematically and based on First Order Predicate Calculus.

I worked for Cincom, one of the “big five” DBMS vendors, in addition to being expert in their Network DBMS, we were well schooled in the competitions capabilities, in order to compete seriously. We did not care much for academic papers because the science was already deteriorating, and the best scientists (including all progressions in the science, except for the /RM/ ) were invented by engineers who worked for the DBMS vendors.

In contrast to the ever-changing freeware/whatmewear/vapourware/nowhere filth (massive suite of programs, aka open sore) that is marketed these days as “SQL” and as a “platform”, those were the days of real SQL (compliant with the standard), and real platforms (server architecture). We already had ACID Transaction from 1960 IBM/CICS/TPC, thus all pre-Relational DBMS were heavily Transaction oriented and ACID compliant. Thus the first few SQL platforms were high-throughput, high-concurrency, ACID Transaction Processing engines.

There were only two: IBM and Sybase (Britton-Lee the Database Machine people, implemented an SQL Database Machine), and there are still only two, plus a bastard son of Sybase MS/SQL for the low end of the market.

The filth, including Orable, is neither SQL, nor ACID-compliant. Hint: with the schizophrenic notion of MVCC, they cannot handle even simple contention, let alone high-throughput, or high-concurrency, or ACID. (If you wish to comment on this point, there is a separate thread open, begging for progress.)

Methods

Re methods, it was a matter of moving from the established pre-Relational methods to the Relational methods, as opposed to inventing methods for the first time. We did not have, and certainly did not dry about not having, Modelling Tools: we drew diagram on paper, using a stencil. We never heard of, nor used, ERD. Apparently it made a big splash in the academic circles.

Note well, the /Relational Model/ is a single paper that defines a single method, like all academic papers, it defines one thing, it cannot be expected to define related things (such as database design or data modelling or how to blow ones nose without getting snot on ones hands). It is telling that the pig-poop eaters (Date; Darwen; Fagin; and all their followers) wring their hands and wail about “Codd did not define this or Codd did not define that ...). Practitioners are fully capable of continuing the data modelling and database design methods while conforming to the new /RM/, without the need to be fed from a baby bottle.

In 1983 Robert Brown extended his modelling method Logical Database Design Technique to cater for the Relational Paradigm. It became used by a few important customers such as DoD, and thus became known to all DBMS vendors (I personally wrote a database for DoD in Cincom’s TOTAL DBMS), and eventually all their customers. It became widely known by 1987, when the first product ERwin came out (first by LogicWorks, and later by Computer Associates). The IDEF people took it over, named it IDEF1X (following IDEF1 for informational modelling and X for Relational), and maintained it. By 1993 it was a NIST Standard.

Several Data Modelling tools followed, such as PowerDesigner and ER/Studio, but they are nowhere near ERwin in terms of true IDEF1X or platform-neutral implementation.

The point of this thread. In the real world (as distinct from the “world” as concocted by “theoreticians” who allege to serve this space), we have:
- the real /Relational Model/ 1970,
- the real Relational Data Modelling method IDEF1X since 1983 (1987 as a product), and
- real SQL platforms since 1981.

The question begs:
- why is that unknown to the “theoreticians” ?
- why do the pig poop eaters NOT teach Relational Data Modelling ?
--- why do they NOT teach IDEF1X ?
- why do they teach instead the defunct; obsolete; anti-Relational ERD ?

These sad people are operating FIFTY YEARS behind the leading edge AFA the /RM/ is concerned, FORTY YEARS behind the leading edge AFA Standards and SQL Platforms are concerned.

Great news. There is one single academic across the entire planet, who has started a journey from the anti-Relational-marketed-as-Relational land that is their studied home, across the great divide, to the Relational world. We touched on the subject in another thread, but it deserves its own thread, so I have brought it here.
> On Wednesday, 24 March 2021 at 23:27:48 UTC+11, Nicola wrote:
> > On 2021-03-24, Derek Ignatius Asirvadem <derek.a...@gmail.com> wrote:
> >
> > In case you missed them. Could you please respond to these questions.
> >
> >> On Thursday, 18 March 2021 at 14:38:13 UTC+11, Derek Ignatius Asirvadem wrote:
> >> > On Tuesday, 16 March 2021 at 23:23:28 UTC+11, Nicola wrote:
> >>
> >> > Note that the "circularity" in that diagram is only apparent (ERD are
> >> > misleading).
> >>
> >> So, why in heavens name, do professors teach ERD ?
>
> I cannot speak for anyone else...

First, let me thank you for your very interesting and considerate response.

> One reason is Chen's Entity-Relationship models are likely perceived as
> easier to grasp for novices than something like IDEF1X. Whether that is
> a correct perception, it can be debated. Another reason is probably just
> historical, due to the huge influence of Chen's seminal paper.

It may have been seminal for the academics, let me assure you, it was not seminal, or even great, for practitioners of the day. It does not have a semantic base, whereas the /RM/ and IDEF1X does.

For academics. I can grant, up to 1970, the paper was amazing. After 1970, it was ageing, badly. By 1983, it was dead; obsolete; defunct; superseded.

Ok, to rephrase the question, why was that pre-Relational method being taught after 1983, and why is it still being taught after the advent of the /RM/, after the /RM/was proved, and after the first genuine SQL platforms came out (1983), and after IDEF1X came out (1983 to practitioners, 1989 as a product, 1993 as an international standard) ?

Novices grasp anything you give them, so the responsible professor gives them the right thing, not cabbage patch dolls for Computer Science.

> In a general setting, ERD is fine for teaching the basics of modeling:
> entities, relationships, generalizations. For someone who has never done
> it, taking a description in a natural language and analyze it to distill
> such concepts and put them in diagrammatic form is not a trivial task
> (well, it's not trivial even for experts!).

> ERDs can be useful as
> a gentle introduction to such topics.
>
> ERD can be introduced without any background knowledge in databases

For introductory levels, show them IDEF1X/Entity level.

> (although that is true about IDEF1X to some extent, when you are
> teaching IDEF1X you are in fact teaching the Relational Model),

Yes !!! Instead of whatever mumbo jumbo that is NOT Relational. That is pretty much the central point. To think about data in terms of the /RM/, not in terms of the physical records that the freaks can contrive in their little crania, because they cannot grasp the /RM/.

> and even
> for purposes that are different from mapping into the Relational Model.
> For instance, one may use ERDs in the context of programming—say, to
> design a game.

Data, the /RM/, is not application dependent. It is data dependent. It is far superior to any other method or non-method or non-thinking.

> When it comes to using ERD vs IDEF1X for designing Relational databases,
> my experience is as follows:
>
> - when teaching ERDs, one also has to explain the rules to translate
> them into the RM:

One can’t. I don’t. I didn’t in the example. It is like translating the thinking that goes into rap “music”, into the thinking that goes into Beethoven’s Fifth. Don’t. Just think classical music. Don’t draw a diagram that has an inferior understanding of data (actually NO understanding of data), and then attempt to translate it into a higher form. No, think in the higher form. and then draw the higher form.

> this is a layer of accidental complexity that IDEF1X
> completely eliminates.

Yes. And it does so by design, not by accident.

> - On other hand, when teaching IDEF1X one has to introduce a richer
> language, so it doesn't take less time to teach than ERD; but I'd say
> that it doesn't take much longer either, as some people might might
> expect.


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Re: "Theoreticians” are Clueless about Relational Data Modelling, Teach Anti-Relational Muddling

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From: nic...@nohost.org (Nicola)
Newsgroups: comp.databases.theory
Subject: Re: "Theoreticians” are Clueless about
Relational Data Modelling, Teach Anti-Relational Muddling
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 by: Nicola - Wed, 31 Mar 2021 11:57 UTC

On 2021-03-29, Derek Ignatius Asirvadem <derek.asirvadem@gmail.com>
wrote:
> Introduction
>
> When it came out in 1970, the Relational Model (Codd, not the
> pretenders) made a paradigm shift in all areas of perceiving data
> (examination; data modelling; storage and retrieval; programming).
> Codd had an uphill battle against the established academics because
> they could not understand it,

I don't think that's a fair assessment. Who are those "established
academics" you mention? *Some* academics may have had issues with Codd's
proposal, but it was definitely understood, and supported, by many other
academics. And certainly at a greater degree than people in industry.
This is confirmed by those who were there:

https://archive.computerhistory.org/resources/access/text/2015/06/102702111-05-01-acc.pdf

E.g., quote from p. 8:

"So Codd's paper got some traction in the academic community where these
mathematical concepts were very familiar. It didn't, at first, get much
traction in the commercial database community. They had their
navigational systems. [...]"

Another first-hand historical perspective is provided by:

https://www.mcjones.org/system_r/sql_reunion_95/sqlr95.html

Quote from the "Prehistory" section:

"[...] Nevertheless, what kicked off this work [on project Gamma-0 and,
eventually, System R] was a key paper by Ted Codd - was it published in
1970 in CACM?

- Yes.

- A couple of us from the Systems Department had tried to read it -
couldn't make heads nor tails out of it. [laughter] At least back
then, it seemed like a very badly written paper: some industrial
motivation, and then right into the math. [laughter]"

Those are not academics talking.

Regarding the rest of your historical comments, I do not have anything
to add or object to. Except, perhaps, that the best DBMS in the world
apparently survives in legacy mode now.

> The point of this thread.

Let's come to the point.

>> On Wednesday, 24 March 2021 at 23:27:48 UTC+11, Nicola wrote:
>> One reason is Chen's Entity-Relationship models are likely perceived
>> as easier to grasp for novices than something like IDEF1X. Whether
>> that is a correct perception, it can be debated. Another reason is
>> probably just historical, due to the huge influence of Chen's seminal
>> paper.
>
> It may have been seminal for the academics, let me assure you, it was
> not seminal, or even great, for practitioners of the day. It does not
> have a semantic base, whereas the /RM/ and IDEF1X does.
>
> For academics. I can grant, up to 1970, the paper was amazing. After
> 1970, it was ageing, badly. By 1983, it was dead; obsolete; defunct;
> superseded.

Uh? Chen's ER paper is from 1976. That was a period of intense research
on so called "semantic modelling" (also spurred in part by Codd's work).
IDEF1X relies heavily upon Chen's shoulders. I'd say that the paper has
aged pretty well as we (let me simplify a bit) are still modelling in
terms of entities, relationships and attributes.

IMO, you are conflating the overall contributions of Chen (and others
working on semantic models), which are important, influential and still
relevant, with the specific details of the notation he invented, which
is not ideal for Relational database design.

> Ok, to rephrase the question, why was that pre-Relational method being
> taught after 1983, and why is it still being taught after the advent
> of the /RM/, after the /RM/was proved, and after the first genuine SQL
> platforms came out (1983), and after IDEF1X came out (1983 to
> practitioners, 1989 as a product, 1993 as an international standard) ?

I already told you my point of view.

Come out with a good database book, with a modern, sound, approach to
data modeling based on IDEF1X, and tell your publisher to send a copy
for evaluation to all academic database researchers. There is no
inherent reason why it should not get adopted because it dismisses ERDs
in favor of IDEF1X. Quite the opposite, actually. There is much need for
a really good reference on database design for the XXI century. I can't
recommend anything off the top of my head.

> after IDEF1X came out [in...] 1993 as an international standard)

The FIPS standard has been withdrawn by NIST in 2008. But IDEF1X has
also been an IEEE standard since 1998, and an ISO/IEC/IEEE standard
since 2012.

>> In a general setting, ERD is fine for teaching the basics of
>> modeling
>>
>> ERDs can be useful as a gentle introduction to such topics.
>>
>> ERD can be introduced without any background knowledge in databases
>
> For introductory levels, show them IDEF1X/Entity level.

Sure, I do that.

>> Some may feel IDEF1X is "low-level" (too many details) compared to
>> ERDs.
>
> False: display only the level of detail necessary for any given
> exercise {Entity|Key|Attribute}.

I agree. I did not mean to imply that I think otherwise; just that
a cursory look by someone who knows ERDs but not IDEF1X may lead to such
remarks.

>> Or some may have criticisms along the lines of this analysis:
>>
>> https://www.essentialstrategies.com/publications/modeling/idef1x.htm
>
> God help me. Academics just love to sabotage themselves, and then cry
> about the fact that they have been sabotaged.

Just brought it as an instance of what a superficial look at the
notation may lead to. I do not think that it is a good critical analysis
in any way. And not by an academic either.

>> My main complaint with IDEF1X is the treatment of generalization
>> hierarchies, in particular the lack of a correct way to model a total
>> inclusive specialization (A must be one of B1, ..., Bn and it may be
>> any of B1, ..., Bn); the approach I have seen around (e.g., see
>> Thomas Bruce's book or ERwin's manual) does not cover such case in
>> a sound way. And the standard never mentions inclusive
>> specializations, AFAICT.
>
> The problem there is, you do not understand Transactions

Look, as much as it may be disappointing to you: I know. Very well.
I know, in particular, how to deal with specialization hierarchies
transactionally.

> There are several threads in this forum that simply do not progress to
> closure due to the unwillingness of academics to engage, and to learn
> about ACID Transactions.

Yes, I did not feel those discussions were going towards fruitful
directions. But, time permitting, I might eventually return on the MVCC
vs 2PL matter.

> This document may assist somewhat in explanation, noting that the full
> and formal explanation lies in ACID Transactions, which has not
> progressed in this forum, and indeed in academia, since 1970.
>
> https://www.softwaregems.com.au/Documents/Article/Database/Relational%20Model/Subtype.pdf
>
> If there is anything in that doc that is not completely understood,
> please ask.

That's perfectly clear.

>> (“If you drew all the relationships without dashed lines, you would
>> still be able to interpret your model in the same way"). I found it
>> difficult sometimes to convince them that such a distinction is
>> important.
>
> Only in the early stages of data modelling. Once the Keys are
> exposed, and worked, which is the bulk of the modelling exercise, that
> distinction is exposed, and difference is plain.
>
> When engaging the modelling exercise fully, meaning, in order, FOPC;
> the /RM; and IDEF1X as the rendition, and as you confirm “meaning is
> king”, you may realise: - the solid lines define ownership (Extension,
> of the Matter of the parent) - the dashed lines define classification
> (imposition of the Form of the parent)

That's clear, too.

>> Another criticism about IDEF1X is the lack of many-to-many
>> relationships (except in "Level 1"/"ER" diagrams), which sometimes
>> makes it awkward to read a relationship, because it is more natural
>> to skip the intermediate associative entity.
>
> You have the right idea, but not the precise method.

I'm good with your explanation, thanks.

>> >> > In your model, each teacher must always be assigned to at least
>> >> > one course. With
>> >> >
>> >> > (a) such an (unrealistic) constraint, *and*
>> >> Why is that constraint “unrealistic” ? In the real world, it is
>> >> a common; even pedestrian, requirement. We have been implementing
>> >> such in Relational databases since 1983.
>> I was thinking more in terms of "department employees", one of whose
>> duties may be teaching (but they may not be teaching all the time).
>> But sure, you may think in terms of employees who teach (a subset of
>> all the employees): then they must teach something, of course.
>
> Sorry, that is not what I meant.
>
> Let me rephrase the question. Why do professors commonly labour and
> state that a 1::1-to-n relation is difficult, why do they pretend it
> is uncommon ?


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Re: "Theoreticians” are Clueless about Relational Data Modelling, Teach Anti-Relational Muddling

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From: nic...@nohost.org (Nicola)
Newsgroups: comp.databases.theory
Subject: Re: "Theoreticians” are Clueless about
Relational Data Modelling, Teach Anti-Relational Muddling
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 by: Nicola - Wed, 31 Mar 2021 15:54 UTC

On 2021-03-31, Nicola <nicola@nohost.org> wrote:
> Regarding subtyping, my critique is specifically on the notation given
> in ERwin Methods Guide at the crossing of "Complete" with "Inclusive
> Subtype". Let me denote the specialization symbol with `-O||`, and
> a categorization cluster with `P -O|| {C1, ..., Cn}`.
> By definition, P -O|| {C1, ..., Cn} means:
>
> "P must be exactly one of C1, ..., Cn".
>
> If an entity P has two ore more clusters, each should be interpreted as
> above. For instance:
>
> P -O|| {A,B}
> P -O|| {C,D}
>
> reads as:
>
> - P must be (exactly) one of A and B; and
> - P must be (exactly) one of C and D.
>
> The notation I'm criticizing corresponds to:
>
> P -O|| {A}
> P -O|| {B}
>
> which, by the definition above, one should read as:
>
> - P must be A; and
> - P must be B.
>
> Instead, the assumed interpretation is:
>
> - P must be A or B; and
> - P may be both A and B,
>
> which is inconsistent with the general definition.

More precisely, it is inconsistent with IDEF1X's ISO (or FIPS) standard.

In a previous post I wrote that ERwin's (i.e., Bruce's) interpretation
is not sound. That is not correct. The interpretation above is well
defined. It is not entirely satisfying, though, because it introduces an
exception in the interpretation of the complete categorization symbol:
the "completeness" (in the sense that each instance of the parent must
be an instance of one of the children) applies to the whole cluster
*set*, as opposed to each single cluster, when clusters have one child.
For instance, the figure from ERwin's Guide has two single-child
clusters:

+-----------+
| P |
+-----------+
| |
+--- ---+
| |
O O
----- -----
----- -----
| |
+---------+ +---------+
| A | | B |
+---------+ +---------+

and the assumed interpretation is that every instance of P must be an
instance A or of B (or both), as opposed to "every instance of P must be
A, and every instance of P must be B". The latter cannot be expressed
under ERwin's interpretation, but it not very important, because if
"every instance of P is always an instance of A" then A can be absorbed
into P.

IDEF1X's standard, on one hand, removes this exception, by stating
explicitly that, in each complete categorization cluster, each instance
of the parent must always be an instance of one of the children—even
when the cluster has only one child.

On the other hand, it makes it impossible to express the situation
above, i.e., that "P must be A, B, or both" (complete + inclusive).

I find it somewhat surprising that this aspect has not been clarified
and addressed in the standard, which was last revised in 2019.

Nicola

Re: "Theoreticians” are Clueless about Relational Data Modelling, Teach Anti-Relational Muddling

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Subject: Re:_"Theoreticians”_are_Clueless_about_Relational_
Data_Modelling,_Teach_Anti-Relational_Muddling
From: derek.as...@gmail.com (Derek Ignatius Asirvadem)
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 by: Derek Ignatius Asirv - Fri, 2 Apr 2021 08:58 UTC

Nicola

Thanks for yours.

Before I get into it, let us understand something.

In academia, academics know nothing of the industry, they have a contrived notion of “industry”, namely anyone who uses PissGreNONsql.

Two exceptions. Codd, because he was a genuine academic who went beyond the academics of his time, and he had his head attached to reality (the commercial application). You, because you are trying to understand reality, and that sets you apart from the academics. The main block you have to get over is, the confidence that academics know reality, which is a total fiction..

If Industry means all who use a DBMS, up to ten years ago, basically it excluded freeware, and they used commercial DBMS, PissGreNONsql was unheard of.. Where freeware is used, MyNONsql leads the field. It still does, it is 1,000 times better than PooGoo while remaining in the same NONsql category. But academia only know about the “industry” that uses their pet excreta producer.

Eg. in the Financial & Banking sector, Sybase has 95% share, with MSSQL the rest. Oracle cannot even compete. In high-performance markets (F&B being one category), it is Sybase and DB2, with MSSQL after a large gap. Oracle cannot compete. Freeware is unheard of, no one wants to execute at 10,000 times slower speed or rewrite their “sql” for every new version of the freeware. These are for databases that are permanent, not “refactored” every month or quarter, such as the ever-changing filth that OO/ORM crowd excretes, that academia caters for.

So the market that uses freeware is really the start-ups, the dumb dumb dumb dumb dummies, ignorant of what commercial DBMS provide, aware of only that fraction of DBMS capability that academia bleats about. Start-ups that will not exist in ten years. No one cares about them. Except academia. Because they too, use PooGrossNONsql. And they too have no clue about ACID Transactions or Server Architecture or the features in commercial DBMS that their pet freeware does not have, and will never have. Same as the academics.

In the commercial DBMS industry (ie. the DBMS suppliers), no one knows or cares about the academics, because they are, as evidenced, fifty years behind the industry. As evidenced, there is nothing that academics have come up with that has been implemented in commercial DBMS (except Codd, again). In Sybase (small company) I can assure you from decades of first-hand experience as a Partner, we have hundreds of PhD level scientists. It may even be 1,000, as the company has grown after the acquisition by SAP.

>>>>
Don’t include such things as the hysterical MVCC in that, because “MVCC” is not a real thing, it is a imaginary thing, collectively imagined and collectively assented to, by academia alone. All hail the imbecile Stonebraker and insist that he is a deity. As I posted in the “MVCC” thread, yes, due to the heavy marketing by academia, “MVCC” has become a check-box item, without being understood by those who request it. Thus Sybase have ADDED it on top of the [existing since 1960 in IBM; since 1977 in Britton-Lee; since 1981 in Sybase] Ordinary Locking (aka incorrectly called “Two Phased Locking” or “2PL” by the academics).

To be clear, if the boffin insists of imagining something that is not real, no problem, we add a set of resources, and we erect his fantasy for him. Meanwhile, regardless of what the boffin does, regardless of what multiverse he is fornicating with his beloved sow in, if he executes an SQL verb that does something to the database, it is done in the normal [forty years extant] “2PL” so that he contends with the other users (who are probably not slaves of academia and thus have an attachment to reality, the database content), and resolves that contention, and ADDITIONALLY, we erect his fantasy on the ADDITIONAL resources, and provide/deny his attempt against his fantasy that we have erected for him. It is the way a kind and gentle mental health nurse provides care for her mentally ill and locked up patients, locked up because they insist fantasy is “reality”, which is dangerous to the public.
<<<<

The above are all general points. If you wish to challenge any of them, do so as general points.

> On Wednesday, 31 March 2021 at 22:58:03 UTC+11, Nicola wrote:
> > On 2021-03-29, Derek Ignatius Asirvadem <derek.a...@gmail.com> wrote:
>
> > Introduction
> >
> > When it came out in 1970, the Relational Model (Codd, not the
> > pretenders) made a paradigm shift in all areas of perceiving data
> > (examination; data modelling; storage and retrieval; programming).
> > Codd had an uphill battle against the established academics because
> > they could not understand it,

> I don't think that's a fair assessment. Who are those "established
> academics" you mention?

The main fight was within IBM, with the likes of Date and Fagin, who pretended to be his supporters but as time has told, they are his subverters. There were others, more later.

There is absolutely zero articles in academia reinforcing or progressing the /RM/. That is evidence, for FIFTY YEARS, that academia does not understand it. All the nameless freaks, save one. Likewise there is not a single book that honestly promotes the /RM/ or progresses it. All of them that purport to articulate “Relational Database” promote instead 1960’s Record Filing Systems, based on RM/T, as confirmed in another thread. Even here, you are the only one looking into genuine Relational Data Modelling. The rest promote anti-Relational pig poop.

> *Some* academics may have had issues with Codd's
> proposal, but it was definitely understood, and supported, by many other
> academics.

Name one (prior to 1980, because that was the statement I made). After 1981, when Sybase came out, and the IBM product (many names) was established, yes, academia could no longer deny it.

Try naming one paper written any time after 1970.

> And certainly at a greater degree than people in industry.
> This is confirmed by those who were there:
>
> https://archive.computerhistory.org/resources/access/text/2015/06/102702111-05-01-acc.pdf
>
> E.g., quote from p. 8:
>
> "So Codd's paper got some traction in the academic community where these
> mathematical concepts were very familiar. It didn't, at first, get much
> traction in the commercial database community. They had their
> navigational systems. [...]"

That is not “industry”, that is one voice, and a self-serving one, an academic with no clue about the industry.

I, who worked for one of the big five DBMS vendors at the time, and previously a specialist on DEC (PDP; VAX) have already categorised it as false. Let me assure you that at Cincom, we had many scientists, many mathematicians, who had no problem understanding the /RM/. Yes, we saw the /RM/ as changing the entire landscape. We did not try to “relationalise” the product, thus we had no need to add anything to TOTAL, but the other DBMS vendors did. And that is why Codd had to write his famous Twelve Rules, to ensure that vendors were not fraudulently declaring that they were /RM/ compliant.

(The has progressed to the problem we have today, where even though SQL is THE established Standard, all the freeware and oracle do not comply, but fraudulently declare that they do.)

Likewise, let me assure you that DEC had hundreds of scientists, who understood and implemented the /RM/, their RDBMS called Rdb was brilliant. It still runs in legacy systems on VAX emulators, it still beats Orable by 10,000 times. I am not saying that emulators are good, but there is a market for it, patronised by corporations that do not fix what is NOT broken, which is why they still exist.

That (what you quote) is typical of the propaganda that academia produce and swallow. Waht you might get from guys like me (or any scientist working for a commercial DBMS provider)is, the actual reality. Obviously the thousands of scientists who work for IBM; Sybase; MS, do not even bother with fora such as this, because academics are irrelevant to the real world platforms, only I do.

Chamberlain contradicts himself all over the place, but you won’t catch it. He comes across as being a friend of Codd, but actually, if you examine it, he demeans Codd, sometimes quite subtely. Very dishonest. It is sad that academics view the Chamberlain memories as gospel. Identical to Date. Much like the Stonebraker stupidity, that has no commercial existence, but lives and thrives in academia and in freeware.

On p12 para 2:
“System R ... was not a product that was going to be released commercially. It was a feasibility demonstration. It was proof of the concept that Ted Codd's ideas actually made sense and could be implemented in a robust way. And there was a lot of skepticism about that.”

So the simple evidenced fact, from Chamberlains own mouth, his “memories”, confirms what I said, and he includes himself in that category:

>> Codd had an uphill battle against the established academics because
>> they could not understand it

On p8 para 1:
“Ted thought that we should use this concept [relations] to allow users to interact with stored data in a way that was independent of the physical representation of that data. He called this notion //data independence//”

And on p 8 para 3:
“Codd introduced the notion of relations as an abstraction for stored data, and he explained about //data independence// and why that was important”


Click here to read the complete article
Re: "Theoreticians” are Clueless about Relational Data Modelling, Teach Anti-Relational Muddling

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Subject: Re:_"Theoreticians”_are_Clueless_about_Relational_
Data_Modelling,_Teach_Anti-Relational_Muddling
From: derek.as...@gmail.com (Derek Ignatius Asirvadem)
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 by: Derek Ignatius Asirv - Fri, 2 Apr 2021 09:36 UTC

Nicola

Thanks for yours.

> On Thursday, 1 April 2021 at 02:54:53 UTC+11, Nicola wrote:

Summary answer.

1. We had subtypes prior to RDBMS and IDEF1X. We had diagrams that were primitive compared to IDEF1X, but they worked perfectly well for the DBMS that we did have. We used IEEE notation.
2. So when IDEF1X was published, no one used {Complete|Incomplete}. [Technically, since one could always add a subtype in the future, every cluster might be Incomplete!].
3. The first (and only compliant) product ERwin provided both notations from day one.
4. ERwin Methods Guide was freely available, and even people who did not have ERwin used it as the proper definition for IDEF1X (rather than purchase).

I concur that the IDEF1X Notation for both Subtypes and Relations is inferior.

Therefore, forget about the thing that does not work, that is known to be inferior, that only academics use, and use the thing that does work, that practitioners have used since 1983, the IEEE notation. For both Subtypes and Relations. Every DM that I am aware of used IEEE (except yours, but you are earnestly trying to understand and use the Standard as is, rather than the modified Standard that practitioners use).

----

Nevertheless, I want to make sure that this particular item is resolved, because absolutely everything that occurs in reality can be modelled under FOPC; the /RM/; and IDEF1X. Refer to my Subtype doc for details and specific examples re what I state here.

First, absolutely and always, think of the Basetype+Subtype pair as a single LOGICAL row (I won’t use silly terms such as “tuple”). Rather than as parent-child (which it is in physical, SQL terms).

> On the other hand, it makes it impossible to express the situation
> above, i.e., that "P must be A, B, or both" (complete + inclusive).

If you give me an example (names, not A B C), I would be happy resolve it.

> ... each instance
> of the parent must always be an instance of one of the children—even
> when the cluster has only one child.

A cluster that has only one child is a Normalisation error. It is not a Basetype-Subtype but an optional column and therefore an optional table.

If it is not optional, then it is as you say “absorbed” into the parent.

> I find it somewhat surprising that this aspect has not been clarified
> and addressed in the standard, which was last revised in 2019.

Yes. That is because the Date & Darwen freaks messed with it, and they pushed the totally obsolete IDEF1X notation over the IEEE notation. Same as you did before our discussion. Academia sucks dead sows. Even the notion of “Identity-Type” as an alternative to Keys, is hysterically backward, but hey, it now “validates” the OO/ORM approach..

Cheers
Derek

Re: "Theoreticians” are Clueless about Relational Data Modelling, Teach Anti-Relational Muddling

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Newsgroups: comp.databases.theory
Subject: Re: "Theoreticians” are Clueless about
Relational Data Modelling, Teach Anti-Relational Muddling
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 by: Nicola - Fri, 2 Apr 2021 19:39 UTC

>> Another first-hand historical perspective is provided by:
>>
>> https://www.mcjones.org/system_r/sql_reunion_95/sqlr95.html
>
> 404 - Not Found.

My fault (wrong case):

https://www.mcjones.org/System_R/SQL_Reunion_95/sqlr95.html

I'll come back to the rest at a later time.

Nicola

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Subject: Re:_"Theoreticians”_are_Clueless_about_Relational_
Data_Modelling,_Teach_Anti-Relational_Muddling
From: derek.as...@gmail.com (Derek Ignatius Asirvadem)
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 by: Derek Ignatius Asirv - Fri, 2 Apr 2021 21:45 UTC

> On Saturday, 3 April 2021 at 06:39:42 UTC+11, Nicola wrote:
>
> >> https://www.mcjones.org/system_r/sql_reunion_95/sqlr95.html
> >
> > 404 - Not Found.
>
> My fault (wrong case):
>
> https://www.mcjones.org/System_R/SQL_Reunion_95/sqlr95.html

> On Wednesday, 31 March 2021 at 22:58:03 UTC+11, Nicola wrote:
>
> Another first-hand historical perspective is provided by:
>
> Quote from the "Prehistory" section:
>
> "[...] Nevertheless, what kicked off this work [on project Gamma-0 and,
> eventually, System R] was a key paper by Ted Codd - was it published in
> 1970 in CACM?
>
> - Yes.
>
> - A couple of us from the Systems Department had tried to read it -
> couldn't make heads nor tails out of it. [laughter] At least back
> then, it seemed like a very badly written paper: some industrial
> motivation, and then right into the math. [laughter]"
>
> Those are not academics talking.

No, no, no. Those ARE academics talking. Rather famous ones.

Those articles reinforce my declarations, not yours ! Each has a great understanding of a very narrow field (of research) and each remained clueless about the other fields, even related fields. And far removed from the “industry” and “users”.

At Cincom, let me assure you, we were very aware of that, which is typical in large corps such as IBM, and sought to avoid that sort of problem by having a small team made up of specialists, in one location. TOTAL for DEC/PDP was written by a team of four. I came to Australia to write the “next generation” TOTAL for DEC/VAX with full ACID, our team was five. We did it in 18 months, it was named ULTRA-DBMS. (Later, Cincom missed the Relational bus, and got side-lined.)

Cheers
Derek

Re: "Theoreticians” are Clueless about Relational Data Modelling, Teach Anti-Relational Muddling

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Subject: Re: "Theoreticians” are Clueless about
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 by: Nicola - Sat, 3 Apr 2021 22:27 UTC

On 2021-04-02, Derek Ignatius Asirvadem <derek.asirvadem@gmail.com> wrote:
>> On Wednesday, 31 March 2021 at 22:58:03 UTC+11, Nicola wrote:
>> > On 2021-03-29, Derek Ignatius Asirvadem <derek.a...@gmail.com> wrote:
>>
>> > Introduction
>> >
>> > When it came out in 1970, the Relational Model (Codd, not the
>> > pretenders) made a paradigm shift in all areas of perceiving data
>> > (examination; data modelling; storage and retrieval; programming).
>> > Codd had an uphill battle against the established academics because
>> > they could not understand it,
>
>> I don't think that's a fair assessment. Who are those "established
>> academics" you mention?
>
> The main fight was within IBM, with the likes of Date and Fagin, who
> pretended to be his supporters but as time has told, they are his
> subverters. There were others, more later.
>
> There is absolutely zero articles in academia reinforcing or
> progressing the /RM/. That is evidence, for FIFTY YEARS, that
> academia does not understand it. All the nameless freaks, save one.
> Likewise there is not a single book that honestly promotes the /RM/ or
> progresses it. All of them that purport to articulate “Relational
> Database” promote instead 1960’s Record Filing Systems, based on RM/T,
> as confirmed in another thread. Even here, you are the only one
> looking into genuine Relational Data Modelling. The rest promote
> anti-Relational pig poop.
>
>> *Some* academics may have had issues with Codd's
>> proposal, but it was definitely understood, and supported, by many other
>> academics.
>
> Name one (prior to 1980, because that was the statement I made).
> After 1981, when Sybase came out, and the IBM product (many names) was
> established, yes, academia could no longer deny it.
>
> Try naming one paper written any time after 1970.

Among the papers I know from before 1980 (Codd's papers excluded), I'd
say that it's not hard to find some that are supportive of the RM. Any
that have understood it? Hard to tell... Progressed it? Let's see:
I have a few papers on semantic modeling, which do not qualify; several
papers on data dependencies, normal forms and other purely theoretical
amenities such as closed/open worlds or the computational complexity of
joins, which do not qualify because they are not practical; and a few
papers on physical and systems design (such as the papers on System R),
which might qualify, but they are from the IBM Systems Journal or IBM
Research Labs.

I would consider Grant's 1977's critique on "Null values in a Relational
Data Base" a progress, as it pointed out the inconsistency of Codd's
preliminary proposal for the treatment of nulls. But you'd likely say
that Codd's treatment of nulls was a regression, so Grant would at most
move things back to the start.

I'd rather like to know why you think that, after 1981, papers with
the qualities that you cannot ascribe to '70s papers would exist, and
ask you to name one such paper, if you know any.

Anyway, I appreciate your own recount of those times, albeit somewhat
critical of the sources I have cited. I do not feel qualified to comment
on that any further, though.

>> IDEF1X relies heavily upon Chen's shoulders.
>
> Nonsense. Give one example, one article. Rob Brown already had
> a diagrammatic modelling method (as distinct from the various diagrams
> that data modellers created) that was widely accepted ... after
> consultation with Codd, he produced what became known as IDEF1X.

FIPS 184, Background section: "The theoretical roots for [the initial
approach to IDEF information modeling] stemmed from the early work of
Dr. E. F. Codd on relational theory and Dr. P. P. S. Chen on the
entity-relationship model."

And two paragraphs later: "Application within industry had led to the
development in 1982 of a Logical Database Design Technique (LDDT) by R.
G. Brown of the Database Design Group. The technique was based on the
relational model of Dr. E. F. Codd, the entity-relationship model of Dr.
P. P. S. Chen, and the generalization concepts of J. M. Smith and D. C.
P. Smith."

> Ok, fine. But your words contradict that, you can’t say that and also
> say “My main complaint with IDEF1X is the treatment of generalization
> hierarchies”.
>
> So what, if anything, is your remaining complaint re “generalization
> hierarchies”.

My complaint is not about "generalization hierarchies" per se. It is
a specific critique on the specific notation used by IDEF1X. That has
nothing to do with understanding transactions, or whatever. It is the
lack of a way (if you follow the standard) or a cumbersome way (if you
follow Bruce/ERwin) to represent what in your document is called
"Non-Exclusive Subtyping", using the "complete categorization" symbol.

>> Regarding subtyping, my critique is specifically on the notation given
>> in ERwin Methods Guide at the crossing of "Complete" with "Inclusive
>> Subtype".
>
> What “crossing” ???

I did not express myself clearly. I meant the IDEF1X (not IE) notation
at the intersection of the "Complete" column and "Inclusive Subtype"
row.

> You can’t use both IDEF1X and IEEE notation in any single model, they
> cannot be mixed. They are exclusive. You can’t go back-and-forth
> either.

Sure, sorry if what I wrote seemed to imply that.

> Sorry. I don’t understand what you are trying to say.

My fault, not the best example of clarity. But the point is, in
a nutshell, that non-exclusive subtyping is not straightforward as it
should be (as it is in IE).

>> > Here is a quick document that clarifies the issues you questioned,
>> > that I have answered. To be complete, I have added an item re
>> > Rolenames, because it is the third common “issue” that people raise:
>> > https://www.softwaregems.com.au/Documents/Article/Database/Relational%20Model/IDEF1X/Nicola%20IDEF1X%202.pdf
>>
>> A question: what is the use case for an association that does not imply
>> a foreign key (rightmost symbol in your "improved IE")? Why would you
>> require a parent entity to exist at the time of insertion, but not
>> later?
>
> It is actually a very common requirement. Refer this Data Model:
> ____https://www.softwaregems.com.au/Documents/Student_Resolutions_2020/Giannis/RoomMonitor%20DM%20V0_51.pdf

I have had time only for a cursory look at the requirements and the
model, but one thing that I have noticed is that there is no independent
Sensor entity. That strikes as something unusual. It's ok to associate
a Reading with a Room for auditing, but with an independent Sensor you
should also be able to maintain referential integrity even when
a sensor's location is changed as the MAC is immutable. But, again,
I need to re-read your requirements.

> Since we are discussing IDEF1X, you might be interested in this Q&A:
> ____https://stackoverflow.com/q/4132044/484814

Interesting reading, thanks.

Nicola

Re: "Theoreticians” are Clueless about Relational Data Modelling, Teach Anti-Relational Muddling

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Newsgroups: comp.databases.theory
Subject: Re: "Theoreticians” are Clueless about
Relational Data Modelling, Teach Anti-Relational Muddling
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 by: Nicola - Sat, 3 Apr 2021 22:40 UTC

On 2021-04-02, Derek Ignatius Asirvadem <derek.asirvadem@gmail.com> wrote:

>> On the other hand, it makes it impossible to express the situation
>> above, i.e., that "P must be A, B, or both" (complete + inclusive).
>
> If you give me an example (names, not A B C), I would be happy resolve it.

The example from your Subtype.pdf document is fine: a PastTime (P) must
be a PasttimeHobby (A) or a PasttimeSport (B), or both.

Using standard IDEF1X symbology, and following the text of the standard
(FIPS 184 or ISO 31320:2, they don't differ on this), you cannot express
the assertion above, only approximate it, AFAICS.

In Bruce's book (and in ERwin) you'd use two clusters, each with one
child, but that requires an interpretation that does not find
an equivalent in the standards. At least, to the best of my
understanding.

Nicola

Re: "Theoreticians” are Clueless about Relational Data Modelling, Teach Anti-Relational Muddling

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Subject: Re:_"Theoreticians”_are_Clueless_about_Relational_
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From: derek.as...@gmail.com (Derek Ignatius Asirvadem)
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 by: Derek Ignatius Asirv - Sun, 4 Apr 2021 09:05 UTC

Nicola

> On Sunday, 4 April 2021 at 08:40:19 UTC+10, Nicola wrote:

Thanks for yours.

> > On 2021-04-02, Derek Ignatius Asirvadem <derek.a...@gmail.com> wrote:
>
> >> On the other hand, it makes it impossible to express the situation
> >> above, i.e., that "P must be A, B, or both" (complete + inclusive).
> >
> > If you give me an example (names, not A B C), I would be happy resolve it.
>
> The example from your Subtype.pdf document is fine: a Pastime (P) must
> be a PastimeHobby (A) or a PastimeSport (B), or both.
>
> Using standard IDEF1X symbology [excluding IEEE notation], and following the text of the standard
> (FIPS 184 or ISO 31320:2, they don't differ on this), you cannot express
> the assertion above, only approximate it, AFAICS.

The "or both" is not a Predicate, it is a collection of instances.

It appears this is boiling down to:
- you do not accept the IEEE notation for Relational Data Modelling
- you are in denial that IEEE notation exists
--- in fact it existed before you or I were born
- you do not accept correction of an incomplete Standard
--- even if the correction existed prior
--- or put otherwise, IDEF1X Subtype notation is a regression, and thus invalid
- therefore for you there is only the IDEF1X notation

Yes, the IDEF1X Subtype notation is broken. Yes, that is just one of the many things that one should be able to (a) model, and (b) model compliant with the /RM/, that cannot be rendered in IDEF1X/IDEF1X Subtype Notation.

The same problem exists with IDEF1X Cardinality notation.

So freaking what.

If you are a hardened academic, that is all there is in the modelling world, and you can’t accept a Data Modelling job of any kind, because the Standard is broken and you can’t model things that exist in nature correctly.

That is why academics cannot work in the industry that they theorise about. They never the leave university mindset.

Enter the practical man. Drum roll and dancing girls.

The Standard is broken ? No worries, I will fix it.

Please be advised, as detailed in my previous post, we had System Diagrams; File Definition Diagrams long before the /RM/, long before IDEF1X, and we used IEEE notation for Subtypes and Cardinality. Such that when IDEF1X came along, any one who was actually practicing (had diagrams and knowledge of IEEE notation) knew immediately that the IDEF1X Subtype & Cardinality notation was broken; that the well-known and pre-existing IEEE notation was NOT broken, and we used it instead. We viewed the IDEF1X Notation as an esoteric joke. As evidenced in the first product, ERwin, from the very first version (otherwise there is no purpose in it giving both notations).

The problem is, academics like you and the guy who wrote that superficial critique, are (a) hanging onto to the original IDE1X Standard definition, (b) refusing to accept that the IEEE notation existed prior, (c) refusing to accept that the IDEF1X notation is broken, and inferior to the IEEE, and (d) thus maintaining an unresolved space [the Non-Excluded Middle], whereas practitioners have a completely resolved space [the Middle, Excluded].

Whereas science was founded on the Four Laws of Thought, and progressed within those tight boundaries for 2,400 years, and thus such unresolved spaces were absolutely forbidden [Law of the Excluded Middle], with the advent of Modern “science”, the Four Laws; Causality; the Hierarchy, are all denied and suppressed, precisely in order to erect fantasy as “reality”. If you play the role of a medieval monk for a few moments, intending to obtain the reward of heaven (eg. no lies; no misrepresentations; no omissions):
- the Middle [d] is not acceptable, it must be Excluded, it would motivate you to obtain resolution
- the denial of reality in [b][c] has to be removed, reality must be admitted, otherwise you would be insane
- you will arrive at the determination that the published Standard is incomplete; unusable as is
- petition ISO to correct the published Standard, to use the pre-existing and not-broken IEEE notation
- use the pre-existing and not-broken IEEE notation until such time as ISO publishes the amendment

Modern academics alone, enjoy the luxury of wringing their hands because a Standard is incomplete, and can only do so in their ivory towers; their protected safe spaces, and in denial of reality. They get to argue; to debate; to discuss, things that are closed; resolved; unarguable to practitioners, and to do so for decades after resolution has been achieved in reality. These two items were closed in the 1980’s in manual diagrams, closed with the first version of ERwin in terms of Data Modelling Tools. But here we are today, forty years after the fact, still arguing about it, as if it has NOT been resolved.

> In Bruce's book (and in ERwin) you'd use two clusters, each with one
> child, but that requires an interpretation that does not find
> an equivalent in the standards. At least, to the best of my
> understanding.

Your understanding is correct.
That interpretation is false.
Bruce is an idiot (per reasons explained above, for noticing the problem and NOT resolving it).
Do not follow an idiot.
Further, the “two clusters with one child each” is a hideous, gross, Normalisation error.
Thus the model is invalid; incorrect, fix it.

The Standard (any Standard) is not a Method. At best, a Standard is a notation, that (a) prevents illegal arrangements by virtue of NOT having a notation for it, and (b) encourages correct definition by having mandatory notation. When a Standard has an error, yet another Standard, usually a higher Standard or a pre-existing one (ie. not your or my private fabrication) is used to correct it or to fill the gap. Issue closed, resolved for practitioners.

As a counter-point, think about UML. Even though it is heavily marketed as a “Standard”, it is not a Standard by any means, because it is (a) grossly incomplete: each modeller adds his own 5 to 10 notations to cover the missing bits because he has designed objects or interaction for which no UML notation exists. When a few hundred do that private dance and publish their models, those 400 or 500 notations become de facto UML, like it or not. Yes, you and I as purists would reject all that. But whereas I would model it in a genuine modelling notation, and thus resolve the issue, you would stand and argue that UML is broken, that the added notation is invalid.

Further, the main fault with UML, its self-destroying fault, is [b] the lack of integration in all areas, The many different diagrams simply do not come together as an integrated System Definition.

The most important missing capability is [c] that which is required for genuine Analysis, and genuine Design: composition/decomposition. Which of course the pre-existing Standards had, and still have. So the practical person uses IDEF1X Corrected for the Data Model; SSADM or IDEF0 for the Process Model; and dismisses UML. Which remains an endless study for the OO/ORM developers obsess about, to draw their precious dingalings in, and to keep replacing. Much like the insane study the toilet bowl. Eg. I could give my Transaction Definitions as UML Methods, which is limited, or as IDEF1X Extensions that include SQL pseudo-code (as in my Subtype doc). They are defined fully in my GUI Definition [interaction] docs.

The converse is, as you are fully aware, OO/ORM developers not-analysing the requirement, then not-designing the process, then obsessing about their Objects that “need persistence”, spending their entire life drawing and re-drawing said Objects, and last but not least, writing records to a ”persistent data store” that gets “refactored” every month or quarter. Viewing both the world, and the requirement through the myopic lens of oo/orm. Maslow’s Golden Hammer syndrome (If all you have in your toolbag is a hammer, every problem looks like a nail).

You have determined that UML is stupid for Data Modelling of any kind, great. You have accepted IDEF1X for Relational Data Modelling, great. You are at the brink of jettisoning ERD, but your blind loyalty to academia prevents you from calling it what it is, and your non-resolution of a simple problem in the IDEF1X Standard prevents you from embracing it.

Thus, I would prevail upon you, given your teaching position, the influence you have on bright eager young minds, to teach only resolutions, not ambiguity or non-resolution. As the industry has done, as they have built thousands of Relational Databases, for forty years.

I have updated this doc to reflect the above. In case there remains anything worth discussing on this issue, I have added a page with the Subtypes, and given the Predicates (which are an excellent method of verifying the model, a feedback loop).

____https://www.softwaregems.com.au/Documents/Article/Database/Relational%20Model/IDEF1X/Nicola%20IDEF1X%202.pdf

Cheers
Derek

Re: "Theoreticians” are Clueless about Relational Data Modelling, Teach Anti-Relational Muddling

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Subject: Re: "Theoreticians” are Clueless about
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 by: Nicola - Sun, 4 Apr 2021 10:50 UTC

On 2021-04-04, Derek Ignatius Asirvadem <derek.asirvadem@gmail.com> wrote:
> The "or both" is not a Predicate, it is a collection of instances.
>
> It appears this is boiling down to:
> - you do not accept the IEEE notation for Relational Data Modelling
> - you are in denial that IEEE notation exists
> --- in fact it existed before you or I were born
> - you do not accept correction of an incomplete Standard
> --- even if the correction existed prior
> --- or put otherwise, IDEF1X Subtype notation is a regression, and thus invalid
> - therefore for you there is only the IDEF1X notation

I am not in denial of anything; I can read your data models without
issues, for instance, and I am not asking you or anyone to use a "more
standard" notation for the sake of it.

That said, yes, I prefer to stick to IDEF1X notation; but I have no
problem diverging from the standard if I need to.

> Yes, the IDEF1X Subtype notation is broken. Yes, that is just one of
> the many things that one should be able to (a) model, and (b) model
> compliant with the /RM/, that cannot be rendered in IDEF1X/IDEF1X
> Subtype Notation.

There are two orthogonal aspects in a generalization hierarchy:

1. are the subtype mutually exclusive or not?
2. is every instance of the parent entity an instance of some child
entity ("subtyping" in your terminology), or not?

So, four combinations. Following the terminology of your document:

| Exclusive?
Subtyping? | Yes No
-----------|----------------------------------------------
Yes | Exclusive Subtyping Non-exclusive subtyping
No | ? Optional attr.[Group], Not Subtype

In IDEF1X notation, "non-exclusive subtyping" is the problematic one.

What is marked with ? corresponds to an "incomplete categorization" in
IDEF1X terminology. Using IE notation, how would you model an
"incomplete categorization"? There is no example in your document.

Concrete example:

- An Employee may be a Consultant;
- An Employee may be a Full-Time Employee;
- An Employee may be neither a Consultant nor a Full-Time Employee;
- An Employee cannot be both a Consultant and a Full-Time Employee.

Note, I am not asking you how you would *implement* this situation; only
how a data model would look like.

> The same problem exists with IDEF1X Cardinality notation.

Which problem do you have with IDEF1X cardinalities?

>> In Bruce's book (and in ERwin) you'd use two clusters, each with one
>> child, but that requires an interpretation that does not find
>> an equivalent in the standards. At least, to the best of my
>> understanding.
>
> Your understanding is correct.
> That interpretation is false.
> Bruce is an idiot (per reasons explained above, for noticing the problem and NOT resolving it).
> Do not follow an idiot.
> Further, the “two clusters with one child each” is a hideous, gross, Normalisation error.
> Thus the model is invalid; incorrect, fix it.

You could also show us how you would solve the example above in ERwin
(with IE notation). I do not have an ERwin license, so I can't try it
myself.

> As a counter-point, think about UML. Even though it is heavily
> marketed as a “Standard”, it is not a Standard by any means, because
> it is (a) grossly incomplete: each modeller adds his own 5 to 10
> notations to cover the missing bits because he has designed objects or
> interaction for which no UML notation exists. When a few hundred do
> that private dance and publish their models, those 400 or 500
> notations become de facto UML, like it or not. Yes, you and I as
> purists would reject all that. But whereas I would model it in
> a genuine modelling notation, and thus resolve the issue, you would
> stand and argue that UML is broken, that the added notation is
> invalid.

Well, one thing is asking to fix something that it's just a notational
glitch that can be easily fixed; "fixing UML" is something on another
level entirely: I'd not dare ask anything like that.

> Further, the main fault with UML, its self-destroying fault, is [b]
> the lack of integration in all areas, The many different diagrams
> simply do not come together as an integrated System Definition.

While I sympathize with your position and I accept the UML analogy for
explanation purposes, I think I have little or nothing to reply to or
disagree with you about UML or ORM (by which I assume you mean
Object-Relational Mapping).

> I have updated this doc to reflect the above. In case there remains
> anything worth discussing on this issue, I have added a page with the
> Subtypes, and given the Predicates (which are an excellent method of
> verifying the model, a feedback loop).
>
> ____ https://www.softwaregems.com.au/Documents/Article/Database/Relational%20Model/IDEF1X/Nicola%20IDEF1X%202.pdf

Yes, the updated chart looks better. IE notation covers subtyping
correctly. My only remaining question is the one above.

RE the added page, looking at the transactions, I think PersonPastime's
subtypes are not exclusive (the diagram has an X that should not be
there).

Happy Easter,
Nicola

Re: "Theoreticians” are Clueless about Relational Data Modelling, Teach Anti-Relational Muddling

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From: derek.as...@gmail.com (Derek Ignatius Asirvadem)
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 by: Derek Ignatius Asirv - Sun, 4 Apr 2021 13:39 UTC

> On Sunday, 4 April 2021 at 20:50:43 UTC+10, Nicola wrote:
>
> Concrete example:
>
> - An Employee may be a Consultant;
> - An Employee may be a Full-Time Employee;
> - An Employee may be neither a Consultant nor a Full-Time Employee;
> - An Employee cannot be both a Consultant and a Full-Time Employee.

I fail to see the problem, I must be missing something. Sorry.

Page 4

> Note, I am not asking you how you would *implement* this situation; only
> how a data model would look like.

There is a difference in your mind ?

Why on earth would I implement something other than what I know the data to be, which knowledge I obtain by modelling it ? Why would I waste time modelling data if I did not have an implementation intent ?

Ok, fine. It is different to you. Why ?

> RE the added page, looking at the transactions, I think PersonPastime's
> subtypes are not exclusive (the diagram has an X that should not be
> there).

Thanks.
Fixed.

By the way, I have given you two ways of transacting a 1::1-to-n relation.

Happy Easter
Derek

Re: "Theoreticians” are Clueless about Relational Data Modelling, Teach Anti-Relational Muddling

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Subject: Re:_"Theoreticians”_are_Clueless_about_Relational_
Data_Modelling,_Teach_Anti-Relational_Muddling
From: derek.as...@gmail.com (Derek Ignatius Asirvadem)
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 by: Derek Ignatius Asirv - Mon, 5 Apr 2021 02:32 UTC

> On Sunday, 4 April 2021 at 08:27:43 UTC+10, Nicola wrote:
> > On 2021-04-02, Derek Ignatius Asirvadem <derek.a...@gmail.com> wrote:
> > > On Wednesday, 31 March 2021 at 22:58:03 UTC+11, Nicola wrote:
> > > > On 2021-03-29, Derek Ignatius Asirvadem <derek.a...@gmail.com> wrote:
> >>
> >> > Introduction
> >> >
> >> > When it came out in 1970, the Relational Model (Codd, not the
> >> > pretenders) made a paradigm shift in all areas of perceiving data
> >> > (examination; data modelling; storage and retrieval; programming).
> >> > Codd had an uphill battle against the established academics because
> >> > they could not understand it,
> >
> >> I don't think that's a fair assessment. Who are those "established
> >> academics" you mention?
> >
> > The main fight was within IBM, with the likes of Date and Fagin, who
> > pretended to be his supporters but as time has told, they are his
> > subverters. There were others, more later.
> >
> > There is absolutely zero articles in academia reinforcing or
> > progressing the /RM/. That is evidence, for FIFTY YEARS, that
> > academia does not understand it. All the nameless freaks, save one.
> > Likewise there is not a single book that honestly promotes the /RM/ or
> > progresses it. All of them that purport to articulate “Relational
> > Database” promote instead 1960’s Record Filing Systems, based on RM/T,
> > as confirmed in another thread. Even here, you are the only one
> > looking into genuine Relational Data Modelling. The rest promote
> > anti-Relational pig poop.
> >
> >> *Some* academics may have had issues with Codd's
> >> proposal, but it was definitely understood, and supported, by many other
> >> academics.
> >
> > Name one (prior to 1980, because that was the statement I made).
> > After 1981, when Sybase came out, and the IBM product (many names) was
> > established, yes, academia could no longer deny it.
> >
> > Try naming one paper written any time after 1970.
>
> Among the papers I know from before 1980 (Codd's papers excluded), I'd
> say that it's not hard to find some that are supportive of the RM. Any
> that have understood it? Hard to tell... Progressed it? Let's see:
> I have a few papers on semantic modeling, which do not qualify; several
> papers on data dependencies, normal forms and other purely theoretical
> amenities such as closed/open worlds or the computational complexity of
> joins, which do not qualify because they are not practical; and a few
> papers on physical and systems design (such as the papers on System R),
> which might qualify, but they are from the IBM Systems Journal or IBM
> Research Labs.

Those may be related, but obliquely. By the fact that that is all there is, you are proving my point: there are no academic papers that support the /RM/, but heaps that support everything but, including RM/T marketed as “Relational Model”.

1. Normal Forms
They are all a complete joke. Half are redundant, the other half are ignorant of the /RM/, and so they “invent” something that is already in the RM (I have written a couple of responses).

That does not count the various changes the Date; Darwen; Fagin gang keep making to the NFs, which are pig poop. None of the idiots have articulated the Normal Forms that are in the /RM/. Maybe if we wait another fifty years.

2. Complexity of Joins
Nothing compared to the papers already written by Sybase Engineers. We have the most intelligent, third generation, Parser and Query Optimiser. You will not believe the level of analysis and reduction of complexity, then determination of access paths based on Statistics. I have read some of those academic papers and cacked myself (I still have difficulty believing that academics are so isolated from the real world, that they read only what their colleagues write, and thus maintain a cocoon).

(In the last 20 years, we have stopped publishing papers, because we do not want to give the freeware crowd the Method, by publishing our Trade Secrets. I have yanked some of my Sybase doco, and there are a few more than I will yank soon. The Sybase Technical Forum has moved out of public view, into a closed SAP-Only stable, so the public don’t get the details even via technical chats.)

3. “Semantic Models”
It appears you do not get it, and this one is going to be hard nut to cut through, because the academic mindset is set and reinforced by many papers. Look, as an academic; as a mathematician; as a logician, why is it that every single diagram you draw is NOT semantic ???

You understand FOPC. FOPC is semantic. That is the foundation of the /RM/.. Now whatever you draw, make sure it is a legal FOPC Predicate, independent, or dependent on other Predicates. Chose your notation, or write one yourself.

The problem is, the academics have concocted this notion of “semantic model”, and written 57 papers about it, with lots of self-serving citations, so they think it is “real”. It isn’t, it is a collectively assented fiction. Much like the problem of “universals”, the freaks deny that Universals exist; what causes their existence; what sustains their existence, and then they concoct a slew of possible ways that “universals” could exist, and they spend the rest of their lives debating the possibilities, never resolving anything. It was resolved in 350BC by Aristotle.

Same here. Academics deny the simple fundamental atomic existence of SEMANTICS, that it is in FOPC already, that conjuring up another “semantics” or forty three is a stupid but income-producing shell game that they can play with each other. Further by denying THE semantic root (FOPC), and then fabricating a “semantic” layer somewhere else, whatever semantics their “semantic” layer has is a mere fraction, and due to incorrect architectural deployment, both massive and hard to design and implement. In any case, it will be grossly incomplete, with no sense of integration.

I will give you a parallel example, which we have discussed to some degree (unfortunately not to closure), the Movie Title Thread. The Relational Data Modeller gave you the Relational Data Model for Movie Title, it has all the FOPC Predicates thought out and modelled. What you engaged in over 14 iterations. Strict FOPC and /RM/, therefore any SQL written against it will be straight-forward (no complexity, /Complexity of Joins/ papers may be irrelevant, yet another academic shell game). In fact any report requirement can be serviced via a single SELECT. But the starting position; the academic position was, “it can’t be done in the /RM/, we need an /ontology/ and a /description logics/“. Don’t mention a fat middleware server, and masses of s/w. Don’t mention that when the perception of data changes, all three layers must be changed, and the “database” has to be “refactored”..

When we insist of FOPC; the /RM/; and genuine Relational Modelling, the /hoontology/ and /descwiption non-logics/ are eliminated, they stand as vacuums. There is no need for an /onotology/ [what a filthy label] to tell the world what the structure of the data is, because the story is told in super integrated form, by the Data Model itself, because the DM is Semantic, because it engages FOPC Predicates.

Another parallel example. FOPC -> Relational Model -> SQL. So real SQL is strictly based on FOPC. But the Torrid Manifesto gulag, the Date; Darwen; Fagin religion totally suppress FOPC and the /RM/, and then assert that SQL is broken. Not only that, they will produce a “data sublanguage” that conforms to the “relational model” which is in fact the anti-Relational RM/T. Thirty years and still nothing.

Meanwhile, back at the farm, guys like me who are unsoiled with their pig poop find absolutely nothing wrong with SQL, there is nothing we cannot do in SQL over a genuine Relational Database.

Do you see what I am trying to say ? Academics are clueless about what SEMANTICS is, that it is already in FOPC, they are therefore clueless about FOPC, what it really and truly is, how the /RM/ isfounded on FOPC. But they write volumes of papers about what “semantics” could be.

> I would consider Grant's 1977's critique on "Null values in a Relational
> Data Base" a progress, as it pointed out the inconsistency of Codd's
> preliminary proposal for the treatment of nulls. But you'd likely say
> that Codd's treatment of nulls was a regression, so Grant would at most
> move things back to the start.

Correct.

Three-valued logic is plain stupid. I have never used it. I have no Nulls in any database, not even from 1983.

It can be understood only in the context that Codd was bending over backwards to get some engagement from the academic community. For ten years. Same as RM/T. A massive regression to pre-1960’s filing systems. Not even 1970’s.

> I'd rather like to know why you think that, after 1981, papers with
> the qualities that you cannot ascribe to '70s papers would exist, and
> ask you to name one such paper, if you know any.

Sorry, I am not sure I understand the question, I will try to answer, but please re-state if I am wrong.


Click here to read the complete article
Re: "Theoreticians” are Clueless about Relational Data Modelling, Teach Anti-Relational Muddling

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Subject: Re:_"Theoreticians”_are_Clueless_about_Relational_
Data_Modelling,_Teach_Anti-Relational_Muddling
From: derek.as...@gmail.com (Derek Ignatius Asirvadem)
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 by: Derek Ignatius Asirv - Mon, 5 Apr 2021 03:59 UTC

> On Sunday, 4 April 2021 at 20:50:43 UTC+10, Nicola wrote:
> > On 2021-04-04, Derek Ignatius Asirvadem <derek.a...@gmail.com> wrote:
>
> > Yes, the IDEF1X Subtype notation is broken. Yes, that is just one of
> > the many things that one should be able to (a) model, and (b) model
> > compliant with the /RM/, that cannot be rendered in IDEF1X/IDEF1X
> > Subtype Notation.

Before I get into the response, as detailed in my previous post, you need to divest yourself of rules or “rules” that you take by implication of the IDEF1X/IDEF1X Subtype definition. And open up to the world of reality, of modelling data as it is, of course in conformation to FOPC and the /RM/ but not conforming to limitations of IDEF1X or anything else (such as physical implementation in limited freeware; etc).

> There are two orthogonal aspects in a generalization hierarchy:

I don’t care for the title, it is some academic artefact, of relevance to academia only. I know that what you mean is the Basetype-Subtype clusters that we have had in databases, decades before those papers were written. And again, I am very interested in modelling data the way it actually exists, not limited to any perception.

Further, I accept wholeheartedly that the correct observation of genus vs species is an essential part of genuine Analysis, here Data Analysis.

> 1. are the subtype mutually exclusive or not?

Ok. One category is. Because they are Exclusive, we [normal people, not prone to reading academic fantasies, unless forced] call the category:
____Exclusive
In Logic, that is an XOR Gate [Discriminator] on the Basetype that identifies the single Subtype. It is Semantic (examples in the progressing doc).

The remaining category, since it is not Exclusive, and certainly not inclusive, is called:
____Non-Exclusive
The Subtypes are not mutually exclusive. There is no Discriminator. Typically, the Basetype has more than one [but not many or all] Subtypes. Note that each Basetype-Subtype pair must be perceived as a logical row.

> 2. is every instance [row] of the parent entity an instance [row] of some child
> entity ("subtyping" in your terminology), or not?

For Exclusive: yes, exactly one Subtype row.
For Non-Exclusive: yes, one or more Subtype rows.

> So, four combinations.

Whoa. What four combinations ??? How can you combine Exclusive with Non-Exclusive ??? You will get “everything”, or scrambled eggs without salami. That is an error at the intellection level, the conceptualisation level. It is invalid.

> Following the terminology of your document:
>
> | Exclusive?
> Subtyping? | Yes No
> -----------|----------------------------------------------
> Yes | Exclusive Subtyping Non-exclusive subtyping
> No | ? Optional attr.[Group], Not Subtype

1. I have dismissed this categorically, as per detail above.
2. I don’t understand it, so much as I would like to respond, I can’t.

> In IDEF1X notation, "non-exclusive subtyping" is the problematic one.

If you say so. But you are mixing things up: in IDEF1X Notation, there is no “Non-Exclusive” Subtyping, there is only {Complete|Incomplete}. If you try to model somethig that your modelling restrictions disallow, you will fail, yes.

Which I find seriously lacking, since {Exclusive|Non-Exclusive} Subtypes existed before the /RM/ and before IDEF1X. Further, I am not about to be restricted by artificial limitations that are part of some notation, so I dismiss it on a second count.

> What is marked with ? corresponds to an "incomplete categorization" in
> IDEF1X terminology.

Ok.

> Using IE notation, how would you model an
> "incomplete categorization"?

Well, you can’t. Because it does not exist in IE. Because it does not exist in reality.

Well you can’t. Because the two methods of classification cannot be mixed.

Nevertheless, because the IDEF1X notation is inferior, a lower-order concept, it can be progressed to a superior, higher-order concept. Just get rid of the notion of “incomplete/complete”.

> There is no example in your document.
>
> Concrete example:
>
> - An Employee may be a Consultant;
> - An Employee may be a Full-Time Employee;
> - An Employee may be neither a Consultant nor a Full-Time Employee;
> - An Employee cannot be both a Consultant and a Full-Time Employee.

I fail to see the problem, I must be missing something. Sorry.

Page 4 added:
____ https://www.softwaregems.com.au/Documents/Article/Database/Relational%20Model/IDEF1X/Nicola%20IDEF1X%202.pdf

> Note, I am not asking you how you would *implement* this situation; only
> how a data model would look like.

There is a difference in your mind ?

Why on earth would I implement something other than what I know the data to be, which knowledge I obtain by modelling it ? Why would I waste time modelling data if I did not have an implementation intent or that is not-for-implementation ? It would be a pathetic relic made of cigar smoke. No thanks.

Ok, fine. It is different to you. Why ?

> > The same problem exists with IDEF1X Cardinality notation.
>
> Which problem do you have with IDEF1X cardinalities?

Sorry, not exactly the same, but a very similar problem. IEEE Cardinality Notation existed prior, and was readily understood. People baulked at the new solid circle plus an alpha character. It was less than expected, a regression to some esoteric concept that was less precise than required for concrete understanding, for implementation (that naughty word again). They were happy with the crows foot that exposed more definition, that they were used to.

If the notation cannot be implemented, then it is something that only theoreticians can use (without confidence). Thus any data modelling notation must have enough definition to host an implementation. The academic notion that theory should not make reference to practice deems the academic unfit for the theory that is the foundation of practice. Which means, we have had no academic; no theoretician, since 1970 and Dr E F Codd.

> >> In Bruce's book (and in ERwin) you'd use two clusters, each with one
> >> child, but that requires an interpretation that does not find
> >> an equivalent in the standards. At least, to the best of my
> >> understanding.
> >
> > Your understanding is correct.
> > That interpretation is false.
> > Bruce is an idiot (per reasons explained above, for noticing the problem and NOT resolving it).
> > Do not follow an idiot.
> > Further, the “two clusters with one child each” is a hideous, gross, Normalisation error.
> > Thus the model is invalid; incorrect, fix it.
>
> You could also show us how you would solve the example above in ERwin
> (with IE notation). I do not have an ERwin license, so I can't try it
> myself.

Done. Page 4.

> > As a counter-point, think about UML. Even though it is heavily
> > marketed as a “Standard”, it is not a Standard by any means, because
> > it is (a) grossly incomplete: each modeller adds his own 5 to 10
> > notations to cover the missing bits because he has designed objects or
> > interaction for which no UML notation exists. When a few hundred do
> > that private dance and publish their models, those 400 or 500
> > notations become de facto UML, like it or not. Yes, you and I as
> > purists would reject all that. But whereas I would model it in
> > a genuine modelling notation, and thus resolve the issue, you would
> > stand and argue that UML is broken, that the added notation is
> > invalid.
>
> Well, one thing is asking to fix something that it's just a notational
> glitch that can be easily fixed; "fixing UML" is something on another
> level entirely: I'd not dare ask anything like that.

Totally. I wouldn’t either. I would extend SSADM to define Objects, only.

> > I have updated this doc to reflect the above. In case there remains
> > anything worth discussing on this issue, I have added a page with the
> > Subtypes, and given the Predicates (which are an excellent method of
> > verifying the model, a feedback loop).
> >
> > ____ https://www.softwaregems.com.au/Documents/Article/Database/Relational%20Model/IDEF1X/Nicola%20IDEF1X%202.pdf
>
> Yes, the updated chart looks better. IE notation covers subtyping
> correctly. My only remaining question is the one above.

Updated again. I have added page 4 with the tentative solution. Tentative, because I don’t think I have grasped the problem you have described.

> RE the added page, looking at the transactions, I think PersonPastime's
> subtypes are not exclusive (the diagram has an X that should not be
> there).

Thanks. Fixed.

By the way, I have given you two ways of transacting a 1::1-to-n relation.

Happy Easter
Derek

Re: "Theoreticians” are Clueless about Relational Data Modelling, Teach Anti-Relational Muddling

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Subject: Re:_"Theoreticians”_are_Clueless_about_Relational_
Data_Modelling,_Teach_Anti-Relational_Muddling
From: derek.as...@gmail.com (Derek Ignatius Asirvadem)
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 by: Derek Ignatius Asirv - Mon, 5 Apr 2021 05:53 UTC

> On Sunday, 4 April 2021 at 08:27:43 UTC+10, Nicola wrote:

> My complaint is not about "generalization hierarchies" per se. It is
> a specific critique on the specific notation used by IDEF1X.
> **That has nothing to do with understanding transactions, or whatever.**

Well it does. It is fair enough that the academics think in terms of fragments, isolated from the context in which it exists.

But that is not the real world, in which things are integrated, atoms are not fragmented. We do not want to entertain something in theory that is not possible in implementation. A database is a single recovery unit. As long as one is using a genuine SQL platform, one has ACID Transactions. The following Predicates for the Basetype::Subtype relation:
__ Basetype is one of {Subtype1|Subtype2|...} -- Exclusive
____ Cardinality 1::1
__ Basetype is any of {Subtype1|Subtype2|...} -- Non-Exclusive
____ Cardinality 1::1-to-n
are implemented by a Constraint (Declaration in SQL). Transactions are declared Constraints (Methods in UML-speak), that provide ACID (if the SQL Platform provides ACID). They form the Database API.

That [SQL platform] gives us confidence that the implied Database Integrity; the Cardinality of 1::1 or 1::1-to-n is possible, and quite ordinary.

Corollary: it is not possible to implement such Database Integrity on freeware and other mickey mouse program suites (they cannot be called “platforms”), that do not have ACID and fraudulently use “SQL” in the label.

Cheers
Derek

Re: "Theoreticians” are Clueless about Relational Data Modelling, Teach Anti-Relational Muddling

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 by: Nicola - Mon, 5 Apr 2021 13:28 UTC

On 2021-04-04, Derek Ignatius Asirvadem <derek.asirvadem@gmail.com> wrote:
>> On Sunday, 4 April 2021 at 20:50:43 UTC+10, Nicola wrote:
>>
>> Concrete example:
>>
>> - An Employee may be a Consultant;
>> - An Employee may be a Full-Time Employee;
>> - An Employee may be neither a Consultant nor a Full-Time Employee;
>> - An Employee cannot be both a Consultant and a Full-Time Employee.
>
> I fail to see the problem, I must be missing something. Sorry.
>
> Page 4

That captures the requirements correctly, but it introduces an entity
(Employee FT_or_C) that does not exist in reality, it is not in the
requirements and, in fact, is not inherently necessary. An IDEF1X model
would have just three entities => IDEF1X is better than your IE by
Occam's Razor. QED

Note that your model, in a larger context, might be a better choice in
some circumstances. But with your modeling language, it's the only one
you can build for the requirements above.

You may counter this, but know in advance that I will not respond,
because for me this matter is settled. The last word is yours!

>> Note, I am not asking you how you would *implement* this situation; only
>> how a data model would look like.
>
> There is a difference in your mind ?

The difference between logical and physical.

> By the way, I have given you two ways of transacting a 1::1-to-n
> relation.

Noticed that. They look good to me.

Nicola

Re: "Theoreticians” are Clueless about Relational Data Modelling, Teach Anti-Relational Muddling

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From: nic...@nohost.org (Nicola Vitacolonna)
Newsgroups: comp.databases.theory
Subject: Re: "Theoreticians” are Clueless about
Relational Data Modelling, Teach Anti-Relational Muddling
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 by: Nicola Vitacolonna - Mon, 5 Apr 2021 13:50 UTC

On 2021-04-05, Derek Ignatius Asirvadem <derek.asirvadem@gmail.com> wrote:
>> There are two orthogonal aspects in a generalization hierarchy:
>
> I don’t care for the title, it is some academic artefact, of relevance
> to academia only. I know that what you mean is the Basetype-Subtype
> clusters that we have had in databases, decades before those papers
> were written. And again, I am very interested in modelling data the
> way it actually exists, not limited to any perception.
>
> Further, I accept wholeheartedly that the correct observation of genus
> vs species is an essential part of genuine Analysis, here Data
> Analysis.
>
>> 1. are the subtype mutually exclusive or not?
>
> Ok. One category is. Because they are Exclusive, we [normal people,
> not prone to reading academic fantasies, unless forced] call the
> category:
> ____Exclusive
> In Logic, that is an XOR Gate [Discriminator] on the Basetype that
> identifies the single Subtype. It is Semantic (examples in the
> progressing doc).
>
> The remaining category, since it is not Exclusive, and certainly not
> inclusive, is called:
> ____Non-Exclusive
> The Subtypes are not mutually exclusive. There is no Discriminator.
> Typically, the Basetype has more than one [but not many or all]
> Subtypes. Note that each Basetype-Subtype pair must be perceived as
> a logical row.
>
>> 2. is every instance [row] of the parent entity an instance [row] of
>> some child entity ("subtyping" in your terminology), or not?
>
> For Exclusive: yes, exactly one Subtype row.
> For Non-Exclusive: yes, one or more Subtype rows.

No, the distinction I have made is between subtyping/not subtyping.

>> So, four combinations.
>
> Whoa. What four combinations ??? How can you combine Exclusive with
> Non-Exclusive ???

I thought that was clear enough, but it mudded the waters instead. It
doesn't matter, though, because the matter is settled for me, as per my
previous post.

>> In IDEF1X notation, "non-exclusive subtyping" is the problematic one.
>
> If you say so. But you are mixing things up: in IDEF1X Notation,
> there is no “Non-Exclusive” Subtyping, there is only
> {Complete|Incomplete}.

Exactly. But "non-exclusive subtyping" is not a notation, it is
a concept. And IDEF1X has not straightforward notation for that.

>> What is marked with ? corresponds to an "incomplete categorization"
>> in IDEF1X terminology.
>
> Ok.
>
>> Using IE notation, how would you model an
>> "incomplete categorization"?
>
> Well, you can’t. Because it does not exist in IE. Because it does
> not exist in reality.

Look who is in denial of reality. My Employee[Full-Time,Consultant]
example is just that. Similarly to the above, "incomplete
categorization" is not a notation, it is a concept. And your IE has not
straightforward notation for that.

> Nevertheless, because the IDEF1X notation is inferior, a lower-order
> concept, it can be progressed to a superior, higher-order concept.
> Just get rid of the notion of “incomplete/complete”.

Without such a notion, you are forced to model "incompleteness" of
a generalization hierarchy with 1:1-0:1 relationships. While you can do
that, it may not be the most natural or more economical way of modeling
some situations, witness your Employee[Full-Time,Consultant] solution.

Nicola

Re: "Theoreticians” are Clueless about Relational Data Modelling, Teach Anti-Relational Muddling

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Newsgroups: comp.databases.theory
Subject: Re: "Theoreticians” are Clueless about
Relational Data Modelling, Teach Anti-Relational Muddling
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 by: Nicola - Mon, 5 Apr 2021 14:32 UTC

On 2021-04-05, Derek Ignatius Asirvadem <derek.asirvadem@gmail.com> wrote:
>> Anyway, I appreciate your own recount of those times, albeit somewhat
>> critical of the sources I have cited. I do not feel qualified to comment
>> on that any further, though.
>
> Hah. You will love the critique I have for the new list of academics,
> above.

Too bad the people you mention, and often insult, are not here to
provide their point of view. You know, the discussion would be much more
interesting.

>> >> IDEF1X relies heavily upon Chen's shoulders.
>> >
>> > Nonsense. Give one example, one article.
>>
>> FIPS 184, Background section:
>
> Yes, it is written.
>
> So what, do you believe everything that is written ?

Never. Not by you, either :-)

Nicola

Re: "Theoreticians” are Clueless about Relational Data Modelling, Teach Anti-Relational Muddling

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Subject: Re: "Theoreticians” are Clueless about
Relational Data Modelling, Teach Anti-Relational Muddling
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 by: Nicola - Mon, 5 Apr 2021 18:48 UTC

On 2021-04-04, Derek Ignatius Asirvadem <derek.asirvadem@gmail.com> wrote:
>> On Sunday, 4 April 2021 at 20:50:43 UTC+10, Nicola wrote:
>>
>> Concrete example:
>>
>> - An Employee may be a Consultant;
>> - An Employee may be a Full-Time Employee;
>> - An Employee may be neither a Consultant nor a Full-Time Employee;
>> - An Employee cannot be both a Consultant and a Full-Time Employee.
>
> I fail to see the problem, I must be missing something. Sorry.
>
> Page 4

This is my comparative assessment of IE vs IDEF1X notation, re
generalization:

https://jirafeau.net/f.php?h=1mnluFoq

Feel free to add your comments, reuse as you see fit, or put on your
site.

Nicola

Re: "Theoreticians” are Clueless about Relational Data Modelling, Teach Anti-Relational Muddling

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Subject: Re:_"Theoreticians”_are_Clueless_about_Relational_
Data_Modelling,_Teach_Anti-Relational_Muddling
From: derek.as...@gmail.com (Derek Ignatius Asirvadem)
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 by: Derek Ignatius Asirv - Wed, 7 Apr 2021 09:51 UTC

> On Monday, 5 April 2021 at 23:28:43 UTC+10, Nicola wrote:
> > On 2021-04-05, Derek Ignatius Asirvadem <derek.a...@gmail.com> wrote:
>
> >> Anyway, I appreciate your own recount of those times, albeit somewhat
> >> critical of the sources I have cited. I do not feel qualified to comment
> >> on that any further, though.
> >
> > Hah. You will love the critique I have for the new list of academics,
> > above.
>
> Too bad the people you mention, and often insult, are not here to
> provide their point of view. You know, the discussion would be much more
> interesting.

Not really. The slaves of the “people I mention”, as well as of the “sources you have cited” post in this forum, so there is no question that their fetid legacy lives on in spirit. They are not here in person, true, but they and their legacy are here, destroying science, and hammering anyone who does not toe the communist party line. It is a protected space for academics.

If you notice the interaction in this forum over the last 15 years, I am the only one who rejects the insanity and takes them on, point by laboured point. I too, did not invent the science, I stand on the shoulders of Science (as defined 350BC to 1911, when the destruction commenced) and Codd, I too, am acting in that spirit, a slave of that system.

So what we have here is the the great war between sanity and insanity, being played out by second generation slaves. It used to be interesting when the golum army was active, but over the years, as O destroyed each of them, they have gone quiet, their only remaining weapon ad hominem, which advertises their position of total loser.

The discussion /was/ interesting. But in the sense of resolution, after the battle is over and the issue has been closed by me, there is not the academic Middle to keep debating, I have Excluded it.

It is with some gratitude that I welcome you, as leaving that crowd, and attempting to cross the great divide into reality (we will have to define that now). But as evidenced, it is slow, moving in fits and starts, often not resolving the issue discussed. And although you are trying hard to grow out of the academic mindset of non-reality, when cornered, you fall back into it.

> insult

Sure, the tone might sometimes be insulting, it is very hard to discuss an idiotic concept without calling it an idiotic concept. But I take pains to ensure the charge is clear. If you have noticed any insult that does not have an underlying charge, please let me know.

I do not retract my insults. You are free to protect the mentally ill; the deranged; the drooling idiots; the purposely evil saboteurs, who are established as academics, from normal humans. You have to decide between your loyalty to freaky academia and the truth.

One the one hand academics argue that an argument from authority is poor, but hysterically, hypocritically, they venerate published academics, regardless of how idiotic their papers are. I don’t hold imbeciles in positions of authority. Genuine authorities rule, and teach. None of you guys do the smallest ruling or tiniest teaching of the science, all of you guys make rulings on anti-Relational filth, and teach anti-Relational pig poop as “Relational”. You want nice treatment ? Go to a brothel. From the real world, you will get disrespect, insults.

What about the fact that for FIFTY years you have come up with nothing, while ranting and railing and caterwauling that you’ve producing the cutting edge of Jello. That is an insult to the undamaged intellect. You insult us, we will insult you back.

Respect is something that is earned, not something that is freely given. You want respect, sure, DO SOMETHING RESPECTABLE. Come up with one thing that articulates or progresses the /RM/, come up with one academic that attacks the fifty years worth of anti-Relational filth. Zero. We get only upset that we did not toe the academic line and genuflect to your imbeciles that never did anything, but tell great stories to interviewers.

Now you are the single exception. Please do not ask me to follow your lead and genuflect to imbecility. Come across the chasm and join me in the real world. Do not run back the safety, the reinforced bastion of insanity, at war with Reality.

> >> >> IDEF1X relies heavily upon Chen's shoulders.
> >> >
> >> > Nonsense. Give one example, one article.
> >>
> >> FIPS 184, Background section:
> >
> > Yes, it is written.
> >
> > So what, do you believe everything that is written ?

You, an established academic, capable of examining these things, did not answer this:

> > When I said “article” I did not mean a report somewhere, I meant a concept, that is recognisable.
> > a. Name one thing, a method or rule or whatever, from the Chen ERD, that exists in IDEF1X.
> > b. Name one thing FROM the /RM/ that Chen has in his ERD.

[a] Therefore there is nothing in IDEF1X that is a contribution or “contribution” from Chen. No evidence at all. Nor surprise because the idiotic Chen ERD does not address the central article of the /RM/, the Relational Key, whereas IDEF1X does, and explicitly.

What is written is lies.

[b] Therefore there is nothing in ERD that can be identified as Relational, not one skerrick.

c. Therefore given that (i) there is nothing Relational in ERD, (ii) the /RM/ has demands that ERD does not supply, (iii) that IDEF1X does supply, the use of ERD by all academics (except possibly you), is an anti-Relational act. Consistent with the freaks suppressing the /RM/, in order to promote their primitive concepts as the /RM/,

> > So what, do you believe everything that is written ?
>
> Never. Not by you, either :-)

Well, the scientific method is to question, to determine if there is evidence, and then to accept. But refusal to accept evidence or denial of reality, is not just unscientific, not just anti-science, but insanity, plain and simple. That passes for academics these days.

The problem with academics is, they believe what the have written, they don’t wait for testing or peer reviews. “Here, MyLittlePony has rainbow mane, you can’t prove that that is false, therefore it is true. QED.” And then if anyone disagrees, they refuse to engage.. “If you don’t believe that MyLittlePony has a rainbow mane, you are anti-semitic or homophobic or worse. I QED-ed you.”

It is a game for small children, devoid of science. But played all the time, by academics, presenting that filth as “science”.

> > On 2021-04-04, Derek Ignatius Asirvadem <derek.a...@gmail.com> wrote:
> >> On Sunday, 4 April 2021 at 20:50:43 UTC+10, Nicola wrote:
> >>
> >> Concrete example:
> >>
> >> - An Employee may be a Consultant;
> >> - An Employee may be a Full-Time Employee;
> >> - An Employee may be neither a Consultant nor a Full-Time Employee;
> >> - An Employee cannot be both a Consultant and a Full-Time Employee.
> >
> > I fail to see the problem, I must be missing something. Sorry.
> >
> > Page 4
>
> That captures the requirements correctly, but it introduces an entity
> (Employee FT_or_C) that does not exist in reality, it is not in the
> requirements and, in fact, is not inherently necessary. An IDEF1X model
> would have just three entities => IDEF1X is better than your IE by
> Occam's Razor. QED

God help me. By virtue of the evidence, you had an agenda from the outset, which was not declared. Then you played a stupid game, no doubt Masters Level, that I was not aware of (I thought you were engaged in honest technical discussion), in order to lead me into a “trap”, and once there, you gleefully declare that the “trap” worked.

Ok, I grant, in the confines of your mind, you “won”. Ok, your academic programming is heavy and deep, and much as you tried to understand normal logic, you could not, you reverted to the mindless, logic-less, academic mindset. You “win” but you learned nothing.

Let’s try again, in the vain hope that honesty, your conscience motivates you to step outside your Masters level trick question.

> >> Concrete example:

Pffft. Nothing concrete about it. It is a concept level, simple Logic, question. Calling it “concrete” merely sets up the deceit for the “trap”. Called an ass a horse does not transform the ass into a horse, it only deems the person as dishonest at best, or a deranged evil “scientist” at worst.

Concept level question:

> >> - An Employee may be a Consultant;
> >> - An Employee may be a Full-Time Employee;
> >> - An Employee may be neither a Consultant nor a Full-Time Employee;
> >> - An Employee cannot be both a Consultant and a Full-Time Employee.
> >
> > I fail to see the problem, I must be missing something. Sorry.
> >
> > Page 4

I answered your concept level question with a concept level answer (note, Lntity level display, not Key level, not Attribute level).

> That captures the requirements correctly, but it introduces an entity
> (Employee FT_or_C) that does not exist in reality,

Course it does.

Your notion of “science” is in fact Materialism; Modernism, which artificially excludes science (Logic; the Four Laws; Causality; Hierarchy; Integration) that we have had from 350BC to 1911, such that you **van** pick out fragments of reality and treat them in isolation, divorced from their context and meaning (remember, you are learning about bringing meaning into the picture, very slowly, but you will not admit that which has excised meaning).


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 by: Derek Ignatius Asirv - Wed, 7 Apr 2021 10:31 UTC

Nicola

> On Tuesday, 6 April 2021 at 04:48:54 UTC+10, Nicola wrote:
> > On 2021-04-04, Derek Ignatius Asirvadem <derek.a...@gmail.com> wrote:
> >> On Sunday, 4 April 2021 at 20:50:43 UTC+10, Nicola wrote:
> >>
> >> Concrete example:
> >>
> >> - An Employee may be a Consultant;
> >> - An Employee may be a Full-Time Employee;
> >> - An Employee may be neither a Consultant nor a Full-Time Employee;
> >> - An Employee cannot be both a Consultant and a Full-Time Employee.
> >
> > I fail to see the problem, I must be missing something. Sorry.
> >
> > Page 4
>
> This is my comparative assessment of IE vs IDEF1X notation, re
> generalization:
>
> https://jirafeau.net/f.php?h=1mnluFoq

There is a problem with that. Actually two. First, let me confirm that my docs are in the public domain, and you are free to use them. But a copyright notice generally means “use as is” and “if used, you must include the copyright notice”. In these days of the internet, that means, most people refer to the doc. Cut-paste is frowned upon, because (a) it can be misused, and (b) the such content is removed from the context.

In future, please feel free to use my docs and to refer to them, please do not-cut-paste.

The second problem is, you have performed a nice Reverse Straw Man. This damages you more than it does me. I have no comment whatsoever re the matter (material) in your doc. I am only addressing the use of my graphics under your headings, your context. I am not saying you are dishonest (a Straw Man is always dishonest), but that in the Modern “science” using the Straw Man is a well established method for “argumentation”, and you are schooled in it; indoctrinated in it, and you are using it unconsciously.

Think about this. In reality, a horse exists. There are pictures of horses. You have a concept, which is an abstraction, not real, it does not exist in reality (I am explaining something, not commenting on your proposition). Let’s call it ABCDEF. So you write it up, and present ABCDEF-1; ABCDEF-2; etc. And under each section, you attach a picture of a different horse.

You might have mulled over thee ABCDEF for years, it might be very “real” to you, but it does not exist. It is a Reverse Straw Man because you have substituted something real for something false (whereas the missionary Straw Man substitutes something false for something real, and then burns it). Because the content that has been substituted belongs to me, it is I who has the task of burning it. Sorry.

You cannot use good graphics under those headings, it is a mis-representation. That is all. Please feel free to re-issue your doc with references [not cut-pastes] to my doc.

This is what respectful correction looks like:
____ https://www.softwaregems.com.au/Documents/Article/Database/Relational%20Model/IDEF1X/Nicola%20Non-Problem%20Proposal%20-%20Response.pdf

> Feel free to add your comments,

If you do not mind, I would rather not. I am very happy to engage with you on all subject matter related to Relational data science, and I would like to maintain that friendliness. I am happy to fulfil your requests, whether answering questions, or providing decent commentary. But your doc, what you are trying to say, is incoherent. Right now there is no problem in the use of IDEF1X, but given your definition thus far, you appear to have created one, and a complex solution to go with the non-problem. I can’t say for sure because the definition is poor.

Further, your intent, the final goal, your agenda, is not declared (but implied).

Therefore I would ask you to excuse me from that request, this one time.

If you care to progress the work to the point of making a coherent proposal, I would be happy to comment. Obviously, prior to that, we can discuss it in this thread, to afford that progress.

Cheers
Derek

Re: "Theoreticians” are Clueless about Relational Data Modelling, Teach Anti-Relational Muddling

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From: nic...@nohost.org (Nicola)
Newsgroups: comp.databases.theory
Subject: Re: "Theoreticians” are Clueless about
Relational Data Modelling, Teach Anti-Relational Muddling
Date: Wed, 7 Apr 2021 18:51:49 +0000 (UTC)
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 by: Nicola - Wed, 7 Apr 2021 18:51 UTC

On 2021-04-07, Derek Ignatius Asirvadem <derek.asirvadem@gmail.com> wrote:
> Nicola
>>
>> This is my comparative assessment of IE vs IDEF1X notation, re
>> generalization:
>>
>> https://jirafeau.net/f.php?h=1mnluFoq
>
> There is a problem with that. Actually two.
> [...]
> In future, please feel free to use my docs and to refer to them,
> please do not-cut-paste.

My apologies. That document is not online any more.

> The second problem is, you have performed a nice Reverse Straw Man.

I think that the misrepresentation is more in the eyes on the beholder.
Anyway, here is a revised document (with references this time):

https://jirafeau.net/f.php?h=2NbPmq6L

What I see is that both notations have deficiencies, which are easily
fixed. Once that is done, they become completely equivalent. IE's only
advantage is being vastly more popular.

Nicola

Re: "Theoreticians” are Clueless about Relational Data Modelling, Teach Anti-Relational Muddling

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From: nic...@nohost.org (Nicola)
Newsgroups: comp.databases.theory
Subject: Re: "Theoreticians” are Clueless about
Relational Data Modelling, Teach Anti-Relational Muddling
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 by: Nicola - Wed, 7 Apr 2021 19:06 UTC

On 2021-04-07, Nicola <nicola@nohost.org> wrote:
> Anyway, here is a revised document (with references this time):

Fixed a typo:

https://jirafeau.net/f.php?h=1WA2Cs0R

Nicola

Re: "Theoreticians” are Clueless about Relational Data Modelling, Teach Anti-Relational Muddling

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Subject: Re:_"Theoreticians”_are_Clueless_about_Relational_
Data_Modelling,_Teach_Anti-Relational_Muddling
From: derek.as...@gmail.com (Derek Ignatius Asirvadem)
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 by: Derek Ignatius Asirv - Wed, 7 Apr 2021 22:15 UTC

> On Thursday, 8 April 2021 at 04:51:55 UTC+10, Nicola wrote:
> > On 2021-04-07, Derek Ignatius Asirvadem <derek.a...@gmail.com> wrote:
> > Nicola
> >>
> >> This is my comparative assessment of IE vs IDEF1X notation, re
> >> generalization:
> >>
> > There is a problem with that. Actually two.
> > [...]
>
> > In future, please feel free to use my docs and to refer to them,
> > please do not-cut-paste.
>
> My apologies. That document is not online any more.

No worries.

> > The second problem is, you have performed a nice Reverse Straw Man.
> I think that the misrepresentation is more in the eyes on the beholder.

I explained my perspective.

> Anyway, here is a revised document (with references this time):
>
> https://jirafeau.net/f.php?h=2NbPmq6L
>
> What I see is that both notations have deficiencies, which are easily
> fixed. Once that is done, they become completely equivalent. IE's only
> advantage is being vastly more popular.

That is a new presentation. Worthy of discussion. Certainly, you may have insights as to why that is so, how you reach that conclusion, but that is unknown to me, you have not discussed it here, so I can neither agree nor disagree.

This post does not respond to that, only to the content in the revised the doc.

> On Thursday, 8 April 2021 at 05:06:08 UTC+10, Nicola wrote:
> > On 2021-04-07, Nicola <nic...@nohost.org> wrote:
> > Anyway, here is a revised document (with references this time):
> Fixed a typo:
>
> https://jirafeau.net/f.php?h=1WA2Cs0R

Responding to issues in the doc only.

0. Intro. Ok, now I know the purpose. Comments are relative to that declaration.

a. Re links. It seems in each instance, the entire text box is “hot”, not just the words in “hot” colour and underlined. Is that what you intend ? It also makes the text in the text box out os reach (eg. for copy-paste).

b. Re Place. In my DM, I am displaying the Entity level symbol for this entity, on a page that is displaying Attribute level. That means that Place is fully defined somewhere else (another page) in the DM. What does the dot-dot-dash line intend to convey ?

c. AK. The order of the attributes has great significance in many areas. In the context of academic data modelling, ok, it has to be given before the Physical. In real life, it is given whenever more than one attribute is defined for the AK. ERwin of course has to demand it, and it does. The mistake is in the ERwin Methods Guide, where the sequence is *not* given and therefore suggests that it is not always required. That is false.

d. Cardinality. The expected (universally understood) notation is:
__ Parent::Child
__ 1::0-to-1 -- eg. optional attribute
__ 1::0-or-1 -- equally understood
This is new:
__ 1:1-0:1

1. Other than the minor issues above, I agree, that is the correct IDEF1X rendition of [Optional Attribute (Not Subtype) ]. But ...

There is no such thing as “Subtype” in IDEF1X. Use “generalisation” and “category” throughout, to be faithful to the IDEF1X terminology.

2. There is no such thing as “Exclusive” “Subtyping” in IDEF1X. I suggest remove the page. Use “generalisation” and “category” throughout, to be faithful to the IDEF1X terminology.

(Subtype; Exclusive, are IEEE terms. Basetype; Non-Exclusive are my corrections to incorrect ERwin terms.)

In a technical doc that recasts IEEE into IDEF1X, I would use only IDEF1X terminology. If you have to make reference to IEEE terms, then label it as such.

3. I know what it is but I have not used Incomplete Categorisation, so my comments on this point exclude that of correctness against [Incomplete Categorisation].

a. You are attempting to use “Partial” as a synonym for Incomplete (not the other way around).
- Why introduce yet another label ? For what purpose ? Is Incomplete not definitive enough ?
- “Partial” is not adequately defined (“not every” does not indicate if 1 is the minimum)

b. I don’t agree with your definition (yellow panel in the middle).. The points are too many, here are a few:
- “is-a” is an ambiguous term, not related to the /RM/ or IDEF1X. If you use it, it needs to be defined.
--- (The IEEE meaning is strictly {Exclusive|Non-Exclusive} = {is one of|is any of}. Some people make it more strict {is exactly one of|is at least one of} but I declare that that is superfluous, the former is easily understood.)
- declarations SUCH AS “business party and a customer must be treated as a single logical unit” are valid for IEEE Subtypes, I don’t see how they apply to IDEF1X Categories.
- in the example, the declaration “business party and a customer must be treated as a single logical unit” violates (a) logic, and (b) IDEF1X Categories.
--- “when the business part[y] is a customer” is contrived.
- the declaration “customer and business party are the same entity” is patently false: the model shows two distinct entities.
- Finally, a Category with a single member is a gross Normalisation error, it is corrected by making it an Optional Attribute.
--- Thus the DM on the left is false (impossible, if being true to IDEF1X terminology; false as detailed above; gross error in Normalisation terms).
--- The DM or the right is the only correct one
- (This may pivot on your understanding of the minimum membership for an Incomplete Category.)
- re “In IE notation, only the model on the right is available” is technically inaccurate. No, the model on the left is false, it fails logic (semantics). The model on the right is not an IE rendition, it is a logically sound model, that happens to be rendered in IEEE.

c. To be clear, in any case (IDEF1X xor IEEE) Customer is definitely not BusinessParty. Go back to the Predicates to check: Business Party is 0-to-1 Customer. Which of course is an optional attribute, an optional Fact, of BusinessParty.

d. Overall for the page. My advice would be to define [Incomplete Categorisation] in generic and definitive terms, using IDEF1X terminology only, THEN draw some comparison to IEEE (if you must, vis-a-vis “recast”). Rather than what you are doing, which is assuming the reader has certain understandings and using mixed IDEF1X/IEEE terms. If you do use IEEE terms, then you must define them.

4-Non-Exclusive Subtyping

a. There is no such thing as “Non-Exclusive Subtyping” in IDEF1X. Since you are trying to recast “Non-Exclusive Subtyping” in IDEF1X, use IDEF1X terms, and put the IEEE terms in double quotes..

I don’t know what the IDEF1X equivalent of “Non-Exclusive Subtyping” would be, or what you think it would be, thus I can’t help you there.

b. This issue may be better discussed in open comms, rather than as an article of issue on this page in this doc. Eg. I don’t accept with “Clusters [Categories] cannot be interpreted individually, but only as a whole” because I don’t know what you mean. On the face of it, it seems false: I can definitely interpret the members of a [IEEE Subtype] Cluster individually.

c. The phrase “translated into predicates” raises a red flag and really grates (I thought you understand Predicates). (I am not correcting your English.) There is no “translation”. Every DM is a graphic representation of the Predicates, every DM is semantic. So the graph can be stated in Predicates; the Predicates are stated in the graph.. Thus “translate” does not apply, it is merely reading THE ONE MODEL in one language (graphic; visual; semantic) or the other (predicates; semantic).

4-Partial Specialization with Mutually Exclusive Child Entities

(No argument with the use of “Exclusive” here)

a. Categorisation, not Specialisation.

b. Re the “Nicola IDEF1X” link. Goes to my doc that supports the entire discussion, progressively: I don’t mind, but is that what you want ? Page 4 specifically, which has changed (as noted in my previous post) ? To me, that page provides a number of models, the purpose of which is to foster discussion in this thread, it is not definitive of anything.

c. So I would say, define [Incomplete Categorisation] in IDEF1X terms first.. And that stands as a reference. THEN define what you are trying to say here, as a progression. I don’t know what that is, so I can’t help you do that articulation.

d. Re the DMs alone, ie. you have looked after [b][c], and the DMs arrive in a reasonable progression. The model below is illegal, because a Category with a single member is a Normalisation error.

e. “Additional entity; additional insert; additional index” is not appropriate considerations at this level of definition. They are performance issues that yes, must be evaluated long before the physical stage, but not at this conceptual stage.

f. Re “to model the situation above using IE notation”, well show the model (in the correct sequence as per [b][c]. It appears you are trying to say that there is a problem with the IEEE notation, so show it.
--- Alternately, explain precisely what “Incomplete Categorisation with Mutually Exclusive Child Entities” means, and I will add it to my Subtype doc, such that your doc remains IDEF1X-faithful, and my doc has a more complete set in IEEE notation, for reference.

g. The new symbol.
Text box on right. I don’t understand how you can apply “Incomplete specialisation [Categorisation]” which is a valid IDEF1X term, to the IEEE classifications, let alone to a specific IEEE symbol, which has a defined meaning totally unrelated to the IDEF1X classifications.
- Further, I do not understand how it is “the same meaning as” the IDEF1X Incomplete Category symbol.


Click here to read the complete article
Re: "Theoreticians” are Clueless about Relational Data Modelling, Teach Anti-Relational Muddling

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Subject: Re:_"Theoreticians”_are_Clueless_about_Relational_
Data_Modelling,_Teach_Anti-Relational_Muddling
From: derek.as...@gmail.com (Derek Ignatius Asirvadem)
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 by: Derek Ignatius Asirv - Thu, 8 Apr 2021 00:54 UTC

> On Monday, 5 April 2021 at 23:50:56 UTC+10, Nicola Vitacolonna wrote:
> > On 2021-04-05, Derek Ignatius Asirvadem <derek.a...@gmail.com> wrote:
> >> There are two orthogonal aspects in a generalization hierarchy:
> >
> > I don’t care for the title, it is some academic artefact, of relevance
> > to academia only. I know that what you mean is the Basetype-Subtype
> > clusters that we have had in databases, decades before those papers
> > were written. And again, I am very interested in modelling data the
> > way it actually exists, not limited to any perception.
> >
> > Further, I accept wholeheartedly that the correct observation of genus
> > vs species is an essential part of genuine Analysis, here Data
> > Analysis.
> >
> >> 1. are the subtype mutually exclusive or not?
> >
> > Ok. One category is. Because they are Exclusive, we [normal people,
> > not prone to reading academic fantasies, unless forced] call the
> > category:
> > ____Exclusive
> > In Logic, that is an XOR Gate [Discriminator] on the Basetype that
> > identifies the single Subtype. It is Semantic (examples in the
> > progressing doc).
> >
> > The remaining category, since it is not Exclusive, and certainly not
> > inclusive, is called:
> > ____Non-Exclusive
> > The Subtypes are not mutually exclusive. There is no Discriminator.
> > Typically, the Basetype has more than one [but not many or all]
> > Subtypes. Note that each Basetype-Subtype pair must be perceived as
> > a logical row.
> >
> >> 2. is every instance [row] of the parent entity an instance [row] of
> >> some child entity ("subtyping" in your terminology), or not?
> >
> > For Exclusive: yes, exactly one Subtype row.
> > For Non-Exclusive: yes, one or more Subtype rows.
>
> No, the distinction I have made is between subtyping/not subtyping.

I do not see how. Your stated heading is “two orthogonal aspects in a generalization hierarchy”. Where is this “distinction between subtyping/not subtyping” ?

> >> So, four combinations.
> >
> > Whoa. What four combinations ??? How can you combine Exclusive with
> > Non-Exclusive ???
>
> I thought that was clear enough, but it mudded the waters instead. It
> doesn't matter, though, because the matter is settled for me, as per my
> previous post.

That response is probably obsolete, please continue the exchange.

How does one COMBINE opposites ??? Naming it “orthogonal” may allow a 2 x 2 grid, but the content would be meaningless. Eg. if you are trying to do something along the lines of the UNCORRECTED ERwin Mthods Guide p69, no, I have corrected it and you have accepted it.

> >> In IDEF1X notation, "non-exclusive subtyping" is the problematic one.
> >
> > If you say so. But you are mixing things up: in IDEF1X Notation,
> > there is no “Non-Exclusive” Subtyping, there is only
> > {Complete|Incomplete}.
>
> Exactly. But "non-exclusive subtyping" is not a notation, it is
> a concept.

???

It is first a concept, absolutely.
It is a concept in IEEE, which existed prior to IDEF1X.
It is a concept outside IDEF1X.
The concept has a notation. (In the same way that a concept has a word.)
The IEEE concept has an IEEE notation.
It is both a concept and a notation.

How can that be denied ???

> And IDEF1X has not straightforward notation for that.

The concept is outside IDEF1X.
It is not that it “has not a straightforward notation”, it has no notation whatsoever for the concept that it does not have.

> >> What is marked with ? corresponds to an "incomplete categorization"
> >> in IDEF1X terminology.
> >
> > Ok.
> >
> >> Using IE notation, how would you model an
> >> "incomplete categorization"?
> >
> > Well, you can’t. Because it does not exist in IE. Because it does
> > not exist in reality.
>
> Look who is in denial of reality.

Stop trying to trip me up. Try to understand what I am saying, in the context of the exchange. Otherwise we will never get to closure.

I am taking the IEEE mindset. If you wish to understand that, and you have to, in order to mount an argument against it, try to understand it. Ask questions. Do not merely perceive the IEEE mindset from a fixed IDEF1X concept-and-notation mindset, because that prevents understanding.

So what am I trying to say in this context ? I have already stated, I cannot understand your cross-hatch pseudo-tabulation. I am trying to understand this thing [?]. You said it “corresponds to an "incomplete categorization" in IDEF1X terminology”. It can’t. Because that thing [incomplete categorization] does not exist in IEEE. It is foreign (not merely “orthogonal”). Stop there and agree/disagree.

----

Now for the next point, after the previous point has been addressed. I say that IEEE does not have [incomplete categorization] because it does not exist in reality. That is not a denial of reality (it is, only if you provide an example of such from reality). A mere declaration will not suffice.

So why do I say such thing, how can it be true ? Because the IDEF1X [incomplete categorization] is not defined, the definition given is not technical, not Relational, not a Predicate that can be implemented (recall, the foundation sequence is: FOPC; /RM/; Modelling; SQL). It is merely “not Complete”.

//For understanding, virtually all Categories, except the most rudimentary (such as Male/Female), would be Incomplete, because they will never be completed, they can be extended in the future. Thus {Complete|Incomplete} fall into the category of meaningless. Thus no one uses it. And particularly since the IEEE Subtypes existed prior, we have no reason to take up this meaningless new categorisation.//

Now if you have a better understanding of IDEF1X[incomplete categorization], or a better definition, please provide.

> My Employee[Full-Time,Consultant]
> example is just that.

No. It is a classroom exercise at the conceptual level only, falsely labelled “concrete”. And then elevated to the status of an universal, by you alone. I have already rejected the requirement as being incomplete, and invalid in terms of providing an example of a generic problem. Yes of course it is IDEF1X[Incomplete] because you made it so, it is your example.

//The burden of proof is on the proposer; the prosecution, not on the defence. It is not for me to disprove your proposal, it is for you to prove it, independently.//

> Similarly to the above, "incomplete
> categorization" is not a notation, it is a concept.

No. As explained above, it is an [IDEF1X] concept first, and an [IDEF1X] notation second. Foreign to IEEE concepts and notation.

> And your IE has not
> straightforward notation for that.

Well, IEEE has NO notation for it, because IEEE has NO concept for it. It is foreign. You can’t fit a square peg into a round hole.

Now if you are trying to say that there is something lacking in the IEEE concepts-and-notation, just explain it, without using IDEF1X concepts-and-notation. If you use your Employee{Full-Time|Consultant} example again, recall I have already proved [not my job] that it is not complete enough to consider as a problem; a lack. The notion that it can be shown in some other notation (eg. Swahili or Chinese pictographs) is irrelevant, it does not prove a lack in the IEEE concepts-and-notation.

Analogy. In the real world, we have only Male/Female, anyone who denies their physical reality is insane. It does not matter what they say they are because they are insane. When a man goes to a doctor and asks for a hysterectomy, he gets treated for insanity, not for a hysterectomy.

Now the insane person comes around, and gleefully declares that his/her/its/shits list of concocted “genders” is better because it has more members and it is forever changing and it will never be complete. That even Fakebook has 104 Genders listed. My response is to give it a sedative and a warm bed. Your response is to declare that there is something lacking in the {Male|Female} set.

Another one. The rag-and-bone man comes along and says he has a child with both male and female organs. Ok, no problem. But then he says it violates the {Male|Female} set. No, it does not, his child is a deformed freak, 0..0001% of the population, due to his wife being his niece. The deformed; the abnormal, prove nothing about the normal, the only thing they prove is about the abnormal.

So if you are trying to say that IEEE concepts-and-notation is lacking in some way, say it squarely, in technical and IEEE terms, not in Swahili; Chinese; insane; or IDEF1X terms.

> > Nevertheless, because the IDEF1X notation is inferior, a lower-order
> > concept, it can be progressed to a superior, higher-order concept.
> > Just get rid of the notion of “incomplete/complete”.
>
> Without such a notion, you are forced to model "incompleteness" of
> a generalization hierarchy with 1:1-0:1 relationships. While you can do
> that, it may not be the most natural or more economical way of modeling
> some situations, witness your Employee[Full-Time,Consultant] solution.


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