Re: shapes-ISSUE-105 (defined prefixes): SHACL SPARQL constraints depend on namespaces in a graph, which is not defined [SHACL Spec]

Does anyone know of an API that doesn't have a Graph-level function to 
query prefixes? Relying on users of SHACL to spell out every full URI in 
their SPARQL queries, or requiring explicit triples to duplicate prefix 
declarations are fatal show-stoppers in terms of useability.

As a resolution, we may need to improve wording in the spec to clarify 
what our assumptions are, e.g. to assume that a SHACL processor must 
preserve prefixes from files so that they can be added into the SPARQL 
query fragments before parsing. This is IMHO an editorial matter.

Holger


On 10/30/15 6:46 AM, Arthur Ryman wrote:
> Peter,
>
> I am not sure this really makes sense since PREFIX is not an RDF
> concept. It is a syntactical concept in most RDF serializations,
> including Turtle of course. However, I believe that even in Turtle,
> you can redefine a PREFIX within the file so there is not necessarily
> a unique meaning for a prefix.
>
> To make prefixes explicit, the shapes graph could include triples to
> explicitly declare the prefixes used in SPARQL code. OSLC defined
> terms for this purpose, e.g. in [1]
>
> @prefix process: <http://jazz.net/ns/process#> .
>
> # prefixes for terms used in the vocabulary
>
> <#process-prefix> a oslc:PrefixDefinition ;
> oslc:prefix "process" ;
> oslc:prefixBase process: .
>
> [1] https://jazz.net/wiki/pub/LinkedData/JazzProcessVocabulary/process-vocabulary.ttl
>
> -- Arthur
>
> On Wed, Oct 28, 2015 at 10:23 PM, RDF Data Shapes Working Group Issue
> Tracker <sysbot+tracker@w3.org> wrote:
>> shapes-ISSUE-105 (defined prefixes): SHACL SPARQL constraints depend on namespaces in a graph, which is not defined [SHACL Spec]
>>
>> http://www.w3.org/2014/data-shapes/track/issues/105
>>
>> Raised by: Peter Patel-Schneider
>> On product: SHACL Spec
>>
>> >From Section 6.2:
>>
>> Before parsing, a SHACL processor must prepend PREFIX statements for all namespace prefixes defined in the current shapes graph.
>>
>> Namespace prefixes are not defined in an RDF graph, so this cannot be done.
>>
>>
>>

Received on Thursday, 29 October 2015 20:59:09 UTC