RE: Temporal validity: alternative for dcterms:valid?

Frans, all,

(Sorry for a latish reply, I'm still catching up on email...)

On Thursday, December 24, 2015 4:57 PM, Frans Knibbe wrote:

> The DCMI Metadata Terms vocabulary seems to have all the basic ingredients
> for building a versioning mechanism in to a dataset (which is or should be a
> very common requirement). Objects in a dataset can have life spans (temporal
> validity), be versions (dcterms:hasVersion/dcterms:isVersionOf) of another
> resource and replace each other (dcterms:replaces/dcterms:isReplacedBy).
> But as Jeni Tennison has noted some time ago (see final section 'Unanswered
> Questions'), a versioning scheme based on DCMI has a weak spot: the property
> for denoting temporal validity (dcterms:valid) is impractical to the point of
> being unusable. Dcterms:valid only takes literals (rdfs:Literal) as value, which
> makes it hard to use it for practical expressions of time intervals. Time
> intervals should be compound objects that are based on useful datatypes. For
> instance, xsd:dateTime (for dates) or xsd:integer (for years or seconds (e.g. in
> UNIX time)) could be used in SPARQL queries to filter or order temporal data.
> In a versioned dataset queries like 'give me all changes between time T1 and
> time T2' or 'give me the state of the dataset at time T3' should be easy to
> create and to resolve. It seems to me that this requires proper and well
> supported data types. A text string notation for time intervals is recommended
> by DCMI: dcmi-period. It is easy and versatile enough, but the average triple
> store probably does not recognize this notation as temporal or numerical data.
> So I wonder if there is a good alternative for dcterms:valid somewhere that can
> be used to indicate temporal validity.

I don't have a solution but only wanted to throw in that this question was discussed on public-lod in November 2013 [1] and that no real conclusion was found there either... That said, I still think an interval datatype similar to the ISO 8601 format ("2007-03-01T13:00:00Z/2008-05-11T15:30:00Z") -- where start and end could be any xsd temporal datatype -- would be useful. Perhaps we can include that in the time deliverable.

[1] starting at https://lists.w3.org/Archives/Public/public-lod/2013Nov/0019.html


Best,

Lars

Received on Tuesday, 12 January 2016 16:41:40 UTC