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Re: PROV-ISSUE-493: prov:type has type Value; valid values too general, include number, datetime, boolean, etc. [prov-dm]

From: Curt Tilmes <Curt.Tilmes@nasa.gov>
Date: Wed, 12 Sep 2012 08:27:59 -0400
Message-ID: <50507FCF.6070105@nasa.gov>
To: <public-prov-wg@w3.org>

I agree with Stephan.  The real reason for having prov:type at all is
to encourage consistency.  Qnames encourage capturing semantic meaning
beyond free text.

The types we've defined
   http://www.w3.org/TR/prov-dm/#term-attribute-type
set a precedent for the type of types we think should fill prov:type,
and the discussion of prov:type in the extensibility points section:
   http://www.w3.org/TR/prov-dm/#extensibility-section
shows examples defining new prov:types as qnames in other namespaces.

This would require some rework of examples, but I think the change
would be valuable in the long term.

Curt

On 09/12/2012 02:19 AM, Stephan Zednik wrote:
> A quick reminder about this issue.
>
> Looking at the PROV-DM document again I see a few examples where simple
> non-qname strings are used for prov:type values.
>
>  From example 21 (http://www.w3.org/TR/prov-dm/#anexample-communication)
>
> prov:type="fine paying, check writing, and mailing"
>
> I think in most if not all of these cases the prov:type value could be
> simplified to a qname.
>
> I understand this change is significant due to the timing of the
> suggestion, but I believe the benefit of making this change is worthwhile.
>
> Thanks,
> --Stephan
>
> On Sep 4, 2012, at 11:18 AM, Provenance Working Group Issue Tracker
> <sysbot+tracker@w3.org <mailto:sysbot+tracker@w3.org>> wrote:
>
>> PROV-ISSUE-493: prov:type has type Value; valid values too general,
>> include number, datetime, boolean, etc. [prov-dm]
>>
>> http://www.w3.org/2011/prov/track/issues/493
>>
>> Raised by: Stephan Zednik
>> On product: prov-dm
>>
>> The value of prov:type is a Value
>> (http://www.w3.org/TR/prov-dm/#term-value) which has the following
>> definition:
>>
>> A value ◊ is a constant such as a string, number, time, qualified
>> name, IRI, and encoded binary data, whose interpretation is outside
>> the scope of PROV. Values can occur in attribute-value pairs.
>>
>> Each kind of such values is called a datatype. Use of the following
>> data types is recommended.
>>
>> The RDF-compatible [RDF-CONCEPTS] types, including those taken from
>> the set of XML Schema Datatypes [XMLSCHEMA11-2];
>> Qualified names introduced in this specification.
>> The normative definitions of these datatypes are provided by their
>> respective specifications.
>>
>> This means that numbers, datetimes, booleans, and unstructured strings
>> are valid values of prov:type.  The prov value section on RDF
>> compliance also seems to suggest there should be a prov:type datatype
>> property in prov-o, which to my knowledge does not currently exist.
>>
>> So my question is, are we ok with numbers, datetimes, booleans as
>> valid values of prov:type?  All of the examples in the DM document
>> appear to use qnames for values of prov:type.
>>
>> Second, is there support for a proposal to restrict values of
>> prov:type to qnames?
>>
>>
>>
>>
>


-- 
Curt Tilmes, Ph.D.
U.S. Global Change Research Program
1717 Pennsylvania Avenue NW, Suite 250
Washington, D.C. 20006, USA

+1 202-419-3479 (office)
+1 443-987-6228 (cell)
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Received on Wednesday, 12 September 2012 12:28:29 GMT

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