Re: [ontolog-forum] master data vs. ontologies

[Thomas Johnston <tmj44p@xxxxxxx>]

@John Bottoms:

John, I keep forgetting that my terminology may not be as clear to others as it is to me. (8>)

The instances are represented by the rows in relational tables. The types of those instances are represented by the tables those rows appear in. The Customer table represents the type Customer -- however that type is defined by the enterprise who owns the database. The rows in that table represent customers. The constraint of entity integrity is the reflection, in database management, of the set-theoretic constraint that nothing can be a member of a set more than once, and that everything that is a member of a set is distinguishable from all other members of that set. This is a fortunate correlation of relational and set theory since relational tables are sets!

Michelangelo's statue of David (that was your message, right?) is not a type, and copies of that statue are not instances of that type. The original is an instance of the type Statue, of course, as well as an instance of the type Great Work of Art; but it is not itself a type and so copies of it are not instances of it.

This is not so much a metaphysical insight as it is a description of generally accepted usage of the relevant terminology.

I hope this helps.

Tom

On Monday, February 16, 2015 7:22 PM, Thomas Johnston <tmj44p@xxxxxxx> wrote:

John,

In your Feb 12th message, you agreed with an earlier contributor who said:

> What the ontologies and master data represent is essentially
> the same thing.

I'm concerned that you agree that "ontologies and master data represent ... essentially the same thing." I'm concerned because I've read, and indeed studied, several of your own books, as well as your excellent edited collection on semantic networks, and I felt pretty sure that I understood you on most points.

But I don't think that master data and ontologies are at all the same thing. Master data, like any data managed in a relational database, is about instances of types of things, those types being represented by the tables in those databases. Ontologies are about formally representing those types, and weaving a network of true statements about them in such a way that automated inferencing can be done on that collection of statements. Indeed, I think I learned this more from you than from anyone else.

Have I misunderstood you?

Regards,

Tom

On Thursday, February 12, 2015 3:13 PM, John F Sowa <sowa@xxxxxxxxxxx> wrote:

Dear Matthew, Alex, David, Ravi, and Kingsley,

MW
> What the ontologies and master data represent is essentially
> the same thing.

I agree.  And the operations performed by a computer program
are just as logical as anything specified in OWL.  (But what
that program does so logically might not be what the programmer
had intended.)

JFS
>> Anybody who has ever written a program that runs correctly
>> on a digital computer is a mathematician.

AS
> if and only if that anybody has proved correctness

My claim does not require a formal proof:

  1. Every digital computer is a logic machine.  And every program
    performs logical operations on strings of bits.  But there is
    no guarantee that what the program does has any relationship
    to what the programmer had intended.

  2. But anybody who has written a program that has performed at
    least one computation as intended has correctly anticipated
    what the computer would do for that computation.

  3. Therefore, that programmer has demonstrated the ability to think
    logically -- at least for that example.  If you want to be 99.9%
    certain, ask the programmer to demonstrate 10 correct results.

DP
> Ontologies are data models written using logic-based languages and
> can cover whatever scope is of interest.

I agree with Matthew that the notation need not be called a logic
for the specification to be called an ontology.  (And it's irrelevant
whether the person who wrote the specification used the O-word).

RS
> Do any mapping tools exist?

Many kinds of mapping tools have been developed.  Logic programming
languages such as Prolog are an example.  UML diagrams can be and
have been mapped to logic, and there are tools for using UML diagrams
(and many similar notations) to generate some or all of a computable
specification.

As Kingsley mentioned, there are also tools that map declarations
for one computable form to declarations for another.

RS
> Are organizations such as OMG and W3C doing it already

Yes.  OMG sponsored the fUML specifications for a subset of UML:
http://www.omg.org/spec/FUML/Current/

I discuss many projects and reports for various kinds of
mappings on the web page "Semantics for interoperable systems":
http://www.jfsowa.com/ikl

John








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