Re: usage of fourth quad element

> On 7 Dec 2015, at 16:31, Ruben Verborgh <ruben.verborgh@ugent.be> wrote:
> 
> Dear all,
> 
> The Representation Task Force is working hard
> on a spec for low-level RDF interfaces.
> For this, we need your input!
> 
> How do you use the fourth element of a quad?
> In other words, quads have one more field
> in addition to subject/predicate/object of triples,
> so what are your use cases for it?
> 
> Your input will help us decide on the naming of this field.
> Current candidates are .graph and .why;
> please see this page for details:
> https://github.com/rdfjs/representation-task-force/wiki/Meeting-2015-12-04#why-or-graph
> 
> Please let us know by Thursday 10 December 2015.
> Thanks in advance for your help!

In LDP you may want to send a SEARCH to a LDPContainer. If you do 
that the natural way to think of this - but I still need to try 
this out - is to have the default graph contain the triples 
of the container itself

<> a lpd:BasicContainer;
  ldp:contains <ldpr1>, <ldpr2>, <ldpr3>.

The contents of <ldpr1>, <ldpr2> and <ldpr3> would then be the 
content of the named graphs.

So you'd like to find the foaf:PersonalProfile documents you'd perhaps
send a SEARCH such as

SELECT ?ldpr
WHERE {
  <> ldp:contains ?ldpr .
  GRAPH ?ldpr { ?ldpr a foaf:PersonalProfileDocument . }
}

It should be possible to return some of the data from the container with named
graphs so that you don't have problems with data in the contained resources 
messing up data about the container itself.  In N3 perhaps something like the
following


<> a lpd:BasicContainer;
  ldp:contains <ldpr1>, <ldpr2>, <ldpr3>.

<ldpr1> { <> a foaf:PersonalProfileDocument ... }
<ldpr2> { ... }
<ldpr3> { ... }

Interestingly since the header information is controlled by the server the server can
actually add that information to the graph directly with

<ldpr1> acl:acl <ldpr1.acl>.
<ldpr2> acl:acl <ldpr2.acl>.
<ldpr3> acl:acl <ldpr3.acl>.


If the server also versions resources then it could do also add to the container information
such as 

<ldpr1> previous <ldpr1.13> .
<ldpr1.13> previous <ldpr1.12> .

graphs importantly help distinguish belief contexts.




> 
> Ruben
> 
> PS Follow our progress here:
> https://github.com/rdfjs/representation-task-force/
> You are welcome to join our weekly meetings:
> https://github.com/rdfjs/representation-task-force/wiki#meetings

Received on Sunday, 28 February 2016 10:38:38 UTC