[OEP] N-ary Relations Summary Review

Below are the most important comments I have on the n-ary relations
note. 
I will follow this up with a more detailed review.

Mike
====

Overall: Excellent, good examples, clearly described.

Good job on being clear and consistent with terminology about relations.

Frequently an abstract comment comes before the example. Often I could
not understand the abstract remark till I read the example. I suggest
putting the examples first in most cases. Then, for readers who may be
interested, state the general principle being illustrated, in more
abstract terms.

I could not find any reason for whether I should choose Pattern 1 over
Pattern 2, in terms of really practical consequences. The only one
seemed to be that it may be intuitively easier to understand. This is
important, but much weaker than other consequences we have discussed in
other notes.

More importantly, patterns 1 and 2 are not only logically equivalent,
but there are no clear guidelines for applying one instead of the other,
it is more a matter of preference. I strongly prefer shifting the
emphasis as follows:
	*	have just one pattern, and two variants - why?
			o	they are logicall equivalent
			o	one morphs into the other merely by
turning around the directin of a relationship arrow (using inverse
function makes them identical)
			o	all of the examples for either P1 or P2
could reasonably be represented using the other pattern, in a way that
seem intuitive and natural to SOMEONE.
	*	clearly state that there no real practical consequences,
of choose one variant instead of another - it is mainly a matter of
personal preference, and what seems more intuitively appealing.
	*	present the guidelines for when to use which variant as
being much less firm than comes across now; use language like: if you
view it this way, then you may prefer pattern 1, if that way, then P2.
The way it reads now, sounds more defnitive, and I think it is much more
fuzzy, than is suggested in the current draft.

Received on Thursday, 12 May 2005 17:35:44 UTC