W3C home > Mailing lists > Public > www-rdf-calendar@w3.org > October 2004

Re: missing types [was: revert recent timezone changes?...]

From: Leo Sauermann <leo@gnowsis.com>
Date: Fri, 22 Oct 2004 10:26:43 +0200
Message-ID: <4178C443.2010605@gnowsis.com>
To: Dan Connolly <connolly@w3.org>
CC: www-rdf-calendar@w3.org, Masahide Kanzaki <post@kanzaki.com>
Masahide,

I would love to hear feedback from you, too, on this topic, as you have 
much practical experience with this questions.

>>i.e. the scheme misses the types
>>#Value_DATE-TIME
>>#Value_DATE
>>    
>>
>
>Missing in what way? I might have known at one time, but I don't
>remember now.
>  
>
trying to explain my concern:

the class #Value_DATE-TIME is used as range of about 20 properties.

but the class #Value_DATE-TIME is not defined.
same with #Value_DATE
(i just looked using text editor. but perhaps I have to look using 
protege? hm...)

so we miss the basic datatype of dates and times, (which renders most of 
an ontology about calendars useless).
(but probably i am wrong as we have used the vocab for years now and 
such a flaw would have emerged in previous implementation efforts)

so IF (there is a problem) THEN

Solutions:
(option 1) // add a class
<rdfs:Class rdf:about="#Value_DATE-TIME">
  ....
</rdfs:Class>

(option 2) // trash this thing and replace it by a standard time notation
delete #Value_DATE-TIME completely and replace it by
http://www.w3.org/2001/XMLSchema#date

I would prefer option 2, as this XMLSchema thing is pretty supported in 
Jena and perhaps other tools.

and I would definitely trash the date-time format defined by vCalendar, 
that is old school date timing. The XML-Schema thing is what we need for 
Semantic Web community, or?

so for example: (solution 2)
  <rdf:Description rdf:ID="completed">
    <rdfs:label>COMPLETED</rdfs:label>
    <rdfs:comment>This property defines the date and time that a to-do 
was actually completed.</rdfs:comment>
    <rdfs:comment>
        value type: DATE-TIME</rdfs:comment>
    <spec:valueType>DATE-TIME</spec:valueType>
    <rdf:type rdf:resource="http://www.w3.org/2002/07/owl#ObjectProperty"/>
    <rdfs:range rdf:resource="http://www.w3.org/2001/XMLSchema#datetime" />
    <rdfs:domain rdf:resource="#Vtodo"/>
  </rdf:Description>

hope that helps to bring the scheme to more use,

cheers
Leo

btw, I think we do not have to slave ourselves under the structures of 
old vocabularies, the terms count.
see for example my vCard scheme hack,
http://www.gnowsis.org/ont/vcard.rdfs

which is not perfect but a little more RDF style structured than
http://www.w3.org/TR/2001/NOTE-vcard-rdf-20010222/

>  
>
>>which is really really bad, as they are used all over the place.
>>or did I miss something here?
>>    
>>
>
>  
>
Received on Friday, 22 October 2004 08:27:10 UTC

This archive was generated by hypermail 2.3.1 : Tuesday, 6 January 2015 20:14:12 UTC