Aaargh! You leave town for 8 years and they change everything!

[sargasso]

Greetings Sparxbeings!,

Just tried EA13 today and by-crikey things certainly have changed around here while I was away. (But judging by a bit of a browse through recent postings there are still some more-experienced (read "old") faces around and there are still some of those wonderful "consistent inconsistencies" abounding.)

Anyway, serious question on theory:

Is there such a thing as a "constrained, enumerated multiplicity"?  By that I mean a multiplicity on an association that can only be one of a set of enumerated multiplicities and that choice is dependent on a value in the owning class. In other words, for a given instance of the subject class where the value of a specific attribute is "x" then the multiplicity of objects related to that instance via that association is exactly "y", where "y" may be a single value or a range.

Consider this example:

class:Religion has attributes Deities and Theism_Type.
class:Deity is associated to Religion through the Deities set.

So, an instance of Religion where Theism_Type = "mono" can/should have 1 and only one Deity instance. Another instance, with Theism_Type = "duo" can/should have exactly 2 Deities instances and so on until the instance with Theism_Type = "multi" can have 1:* Deity instances associated.

My problem is figuring out how to show this type of multiplicity concisely and simply and is not specifically a how to do it EA question.

Any input?

b

p.s. Yes, you may well be thinking "OMG! Someone's left the back gate unlocked and that nutcase has crawled back in again!" 

[Geert Bellekens]

Hi there, and welcome back.

I guess you'll either have to use some kind of constraint on the association, or use subclasses of Theism instead of Theism types. In that case you can give each subclass it's own redefined association with redefined exact multiplicities.

Geert

[KP]

or use subclasses of Theism instead of Theism types. In that case you can give each subclass it's own redefined association with redefined exact multiplicities.

Was going to suggest this but Geert beat me to it.

[Glassboy]

p.s. Yes, you may well be thinking "OMG! Someone's left the back gate unlocked and that nutcase has crawled back in again!" 

No I was actually thinking how the hell are you going to cope with abstraction where deities have different names across pantheons (Zeus vs Juno), or are effectively different gods with the same name at different periods of history (Tyr).  And how you're going to cope with monotheistic religions co-opting deities as "saints ".  Or even syncretic religions.

I think you need to put some more work into your examples :-)

[sargasso]

(The reality is, they are the funny shaped bits of metal on the ends of custom made roof struts - the name escapes me for the moment - we are trying to come up with a way to classify them to reduce the errors between the salespeople, the designing engineers and the fabricators.) Remember those ASCII box drawing characters, they sort of look like them only in three dimensions and there's lots more of them.

Geert has come up with the right answer.  When I first thought about it, I thought gawd there's going to be hundreds of them. But it's looking like there will only be a couple of dozen - which is copable.

Thanks Geert! One of those cases of being too close to the problem.

b