Re: Profiles in Linked Data

On 5/12/15 8:18 AM, Svensson, Lars wrote:
> Kingsley,
>
> On Monday, May 11, 2015 9:00 PM, Kingsley Idehen wrote:
>
>> >We have to be careful here. RDF Language sentences/statements have a
>> >defined syntax as per RDF Abstract Syntax i.e., 3-tuples organized in subject,
>> >predicate, object based structure. RDF Shapes (as far as I know) has nothing to
>> >do with the subject, predicate, object structural syntax of an RDF
>> >statement/sentence. Basically, it's supposed to provide a mechanism for
>> >constraining the entity type (class instances) of RDF statement's subject and
>> >object, when creating RDF statements/sentences in documents. Think of this as
>> >having more to do with what's regarded as data-entry validation and control, in
>> >other RDBMS quarters.
> The charter of the data shapes WG [1] says that "the product of the RDF Data Shapes WG will enable the definition of graph topologies for interface specification, code development, and data verification", so it's not_only_  about validation etc. My understanding is that it's somewhat similar to XML schema and thus is essentially a description of the graph structure. As such, it can of course be used for validation, but that is only one purpose.

Terms from a vocabulary or ontology do not change the topology of an RDF 
statement represented as graph pictorial. Neither do additional 
statements that provide constraints on the subjects and objects of a 
predicate. It is still going to be an RDF 3-tuple (or triple).

>
>> >The function of the "profile" I believe you (and others that support this) are
>> >seeking has more to do with enabling clients and servers (that don't necessarily
>> >understand or care about RDF's implicit semantics) exchange hints about the
>> >nature of RDF document content (e.g., does it conform to Linked Data
>> >principles re. entity naming [denotation + connotation] ).
> No, my use of "profile" is really a "shape" in the sense of the data shapes wg. Some of their motivations are what I'm envisioning, too, e.g.
>
> * Developers of each data-consuming application could define the shapes their software needs to find in each feed, in order to work properly, with optional elements it can use to work better.
> * Developers of data-providing systems can read the shape definitions (and possibly related RDF Vocabulary definitions) to learn what they need to provide
>
>> >Cut long story short, a "profile" hint is about the nature of the RDF content (in
>> >regards to entity names and name interpretation), not its shape (which is
>> >defined by RDF syntax).
> OK, I stand corrected: My question is: How can clients and servers negotiate shape information?

RDF data has one shape. Use of terms from a vocabulary or ontology don't 
change the shape of RDF document content.

"Profiles" are a means of representing preferences. Seeking terms from a 
specific vocabulary or ontology in regards to RDF document content is an 
example of a preference.

You can use "rel=profile" as a preference indicator via HTTP message 
exchanges between clients and servers.

-- 
Regards,

Kingsley Idehen 
Founder & CEO
OpenLink Software
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