Here and there a supporting comment.

 

William Frank wrote:

 

So now, I WRITE "at least one" more than one, etc.   Right on the UML diagram, when multiplicity is an issue. 

 But when you depart, you will lose the UML-educated audience.

[EJB] The problem with UML in this regard is that it defaults to a constraint.  The interpretation of an association end that has no stated multiplicity is ‘exactly one’. 

This is a part of the object-oriented programming background.  The proper default for relationships is 0 or more,

unless the modeler says it is constrained.  But 0 or more is harder to implement in an OOPL – you have to pick a paradigm for arrays or lists.

[EJB] I have a largely negative reaction to the idea that language syntax should enforce “good” modeling practice.  Language syntax should ENABLE _expression_ of intent and PERMIT good modeling practices.  The bitter lesson is that “good practice” in modeling Java programs and “good practice” in modeling databases and “good practice” in modeling the problem space may be different and conflicting. 

I agree with Edward that NIEM/ORM is much better than either of them in expressing the semantics of the world, but he is right that they aren't well enough supported.

[EJB] In my experience the relationship between object-oriented analysis and object-oriented programming differed widely among the authors who wrote about o-o analysis.  I mentioned once to Steve Mellor that I found the Shlaer-Mellor book interesting, and Steve responded “interesting that the two authors clearly disagreed on the meaning of the title”.
 

[EJB]  I would say rather that, if the intent of the formal model is to produce an implementation by rote transformation, then the model is an implementation model.”  And I think David, William, John and I are all in agreement on that part.

[EJB] I see, however, that some of our educated journeyman knowledge engineers think that a good OWL model is one that allows the chosen reasoner to do the test classifications quickly.  It is just another version of making the problem space model the solution model, because the OWL model is the implementation schema.  A clear axiomatic representation of a problem space may need to be restructured, simplified, and assisted with helper axioms and other controls to produce an efficient “theory” for a particular kind of use by a particular reasoner.  Knowledge engineering is an engineering activity, and like the others it has both analytical and solution models.  We should not again make the mistake of assuming that a good analytical OWL model can be judged by the performance of a reasoner.

 

-Ed

 

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