Great alternatives, thanks! All seem to be very useful, though I am indeed not really interested in the 'when', but more in the 'how long' indeed, so the third option will do just fine I think.
Stefan Op woensdag 31 juli 2019 11:59:08 UTC+2 schreef David Price: > > Seems to me you’re trying to manage two concepts you cannot record as one: > “happened at time” and “time taken to occur”. > > I’ve seen both xsd:duration and xsd:dateTime used in real, operational > ontologies in customer projects. However, the main use I’ve seen for > xsd:duration is properties about things that live for years like "equipment > life”. For data about experiments or similar, I’ve seen xsd:dateTime used > far more often. > > A few alternatives: > > 1 - Perhaps two dateTime properties of the action/activity are all you > need: startedOrHappenedAt and endedAt. If endedAt is missing then you know > it happened instantly, if not then duration = endedAt > - startedOrHappenedAt. > > 2 - Alternatively, you could use startedAt and endedAt and set endedAt to > have the same value as startedAt for the “instantly” case. > > 3 - Alternatively, choose the smallest value allowed for xsd:duration and > use that to mean “instantly”. People sometimes choose a seldom-used value > of a datatype and give it a specific meaning. > > The advantage of 2 is that you also record when something happened, not > just how long it took to happen, and so you can order activities and also > always calculate if activities overlapped in time. 1 is one less triple in > the “instantly” case. 3 is perhaps best if you are only ever comparing how > long things took, not when they happened. > > A fourth option you might consider is two subclasses of Activity: > InstantaneousActivity and ContinuousActivity rather than trying to use a > Boolean (which very often means a subclass is missing). > > Cheers, > David > > UK +44 (0) 7788 561308 > US +1 (336) 283-0808 > > -- You received this message because you are subscribed to the Google Groups "TopBraid Suite Users" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/topbraid-users/16f32947-f16d-46b6-a54f-a58e13b35686%40googlegroups.com.
