[sc34wg3] New TMCL slides: at least 2 roles must be played

Patrick Durusau patrick at durusau.net
Mon Nov 23 13:26:01 EST 2009


Steve Newcomb wrote:
> Lars Marius Garshol wrote:
>> I can see a need for omissible role types in n-ary relationships 
>> where it may be the case that one of the role players is not known, 
>> but in binary relationship then if one of the players is not known 
>> you can simply omit the entire relationship.
> I like this rule, but I think it should be more general. Even in an 
> n-ary association, if there's only one role player, there's no 
> relationship, so the whole association is otiose. The rule should be: 
> /At least two roles must be played/.
> The only thing that bothers me about this rule is that there may be 
> moments when an association is only partially expressed. But I'm not 
> sure that it's an issue, really.
Moments when an association is only partially expressed?

Hmmm, ok, what about marriage and one role player known but spouse is 
not? A partial baptism record for example. Not ever going to cure that lack.

May not know who the other role player is but the existence of the 
association is not in doubt.

A subject is lost by omitting the association. That is "a" choice but it 
isn't one that should be a rule for all topic maps.

Hope you are having a great day!


Patrick Durusau
patrick at durusau.net
Chair, V1 - US TAG to JTC 1/SC 34
Convener, JTC 1/SC 34/WG 3 (Topic Maps)
Editor, OpenDocument Format TC (OASIS), Project Editor ISO/IEC 26300
Co-Editor, ISO/IEC 13250-1, 13250-5 (Topic Maps)

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