W3C home > Mailing lists > Public > public-media-annotation@w3.org > April 2011

Re: getting rid of xsd:dateTime ?

From: Felix Sasaki <felix.sasaki@fh-potsdam.de>
Date: Wed, 6 Apr 2011 00:32:28 +0200
Message-ID: <BANLkTik95zEbhwMuEsnJZUGU-+7snYNpgA@mail.gmail.com>
To: Pierre-Antoine Champin <pierre-antoine.champin@liris.cnrs.fr>
Cc: "public-media-annotation@w3.org" <public-media-annotation@w3.org>
2011/4/5 Pierre-Antoine Champin <pierre-antoine.champin@liris.cnrs.fr>

> Hi all,
> there seem to be a recurring problem with dates and the ma: ontology. I
> encountered it, Martin encountered it, I know that Joakim also did...
> The fact is that most metadata formats we are dealing with allow dates
> to be more or less precise, like
> * just a year

in XML Schema, this would be gYear http://www.w3.org/TR/xmlschema-2/#gYear

> * a year and a month

this would be http://www.w3.org/TR/xmlschema-2/#gYearMonth

> * a year, a month and a day

this would be date http://www.w3.org/TR/xmlschema-2/#date

> * ...
> while xsd:dateTime imposes to us to commit to a 1sec precision...
> I suggest we change the range of date properties to rdfs:Literal, and
> specify in the documentation that they should be of the form
> YYYY[-MM[-DD[Thh[:mm[:ss[.fff]]]]]], to be interpreted as an incomplete
> date.

This would be very bad. RDF in many areas is linked to XML datatypes, see
e.g. http://www.w3.org/TR/rdf-primer/#typedliterals , and I would encourage
us to follow this approach as close as possible. To solve your problems, I
would rather say that a date should be one of the above built in XML Schema
data types.


> This hinders interoperability a tiny bit, but not as much as inventing a
> day and an hour for media resources for which we only know the year.
>  pa
> To all, some general remarks and conclusions
> * as most metadata format are more permissive regarding dates than
> xsd:dateTime, I suggest we simply use rdfs:Literal for all our date
> properties, and explain that it should be of the form
> YYYY[-MM[-DD[Thh[:mm[:ss[.fff]]]]]]
Received on Tuesday, 5 April 2011 22:32:56 UTC

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