- From: Ashok Malhotra <ashok.malhotra@oracle.com>
- Date: Fri, 22 Nov 2013 17:27:32 -0500
- To: public-ldp-wg@w3.org
Henry: A couple of points: 1. There is a view that collections are merely views over the triples hosted by the server. That is, a selection of triples by subject and predicate. Your proposal links the collection and its members directly which is contrary to this view. 2. ldp:created would only apply to members created by doing a POST to a collection. What about members created by other means? What about non-RDF members? All the best, Ashok On 11/22/2013 2:34 PM, Henry Story wrote: > On 22 Nov 2013, at 16:40, Eric Prud'hommeaux <eric@w3.org> wrote: > >> * Arnaud Le Hors <lehors@us.ibm.com> [2013-11-21 11:21-0800] >>> Hi all, >>> In an effort to clarify what we currently have in the spec I put a page >>> together on our wiki that I invite you all to read: >>> >>> http://www.w3.org/2012/ldp/wiki/Membership > Impact of making ldp:created mandatory in all cases > =================================================== > > http://www.w3.org/2012/ldp/wiki/Membership#Impact_of_making_ldp:created_mandatory_in_all_cases > > 1. Query Simplicity > ------------------- > > It says that the query becomes: > > [[ > PREFIX ldp: <http://www.w3.org/ns/ldp#> > > SELECT ?ldpc ?resource > WHERE { > ?ldpc a ldp:Container; > ldp:created ?resource. > } > ]] > > In fact the query can be simplified to > > [[ > PREFIX ldp: <http://www.w3.org/ns/ldp#> > > SELECT ?ldpc ?resource > WHERE { > ?ldpc ldp:created ?resource. > } > ]] > > since the domain of ldp:Created is an ldp:Container . > > ( When querying an LDPC the query can be made even more specific by asking > > [[ > PREFIX ldp: <http://www.w3.org/ns/ldp#> > > SELECT ?resource > WHERE { > <> ldp:created ?resource. > } > ]] > ) > > 2. duplication > -------------- > > The text says "This simplifies queries at the cost of extra membership arcs. " > I disagree. If anything ldp:created should be a sub relation of rdfs:member. > ie: > > ldp:created rdfs:subPropertyOf rdfs:member . > > Therefore all the duplicates can be ignored. Ie one only needs the container > to be: > > [[ > @base <http://example.org/container1/> > @prefix dcterms: <http://purl.org/dc/terms/>. > @prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#>. > @prefix ldp: <http://www.w3.org/ns/ldp#>. > > <> > a ldp:Container; > ldp:containerResource <> ; > ldp:containsRelation rdfs:member; > ldp:insertedContentRelation ldp:MemberSubject; > dcterms:title "A very simple container"; > ldp:created <member1>, <member2>, <member3>. > ]] > > 3. in perspective of ldp-ISSUE-85 (causation) & ISSUE-89 (ldp:xyz) > ------------------------------------------------------------------ > > To go one step further, I would argue that if one thinks of > ldp:containerResource, ldp:containsRelation and ldp:insertedContentRelation > as forming a rule on what should happen when one POSTs, and not a way to infer > from membership triples to ldp:created resources ( or more generally to ldp:xyz > resources as defined by ISSUE-89 ) then one can simplify the above to the > following > > > [[ > <> a ldp:Container; > ldp:created <member1>, <member2>, <member3>. > ]] > > or considering ISSUE-89 > > [[ > <> a ldp:Container; > ldp:xyz <member1>, <member2>, <member3>. > ]] > > which of course would be easier to read as > > [[ > [[ > <> a ldp:Container; > ldp:manages <member1>, <member2>, <member3>. > ]] > > That is the point of ISSUE-85 > > > >> Executive summary: >> example data for all patterns of membership triples. >> SPARQL queries which reach all members regardless of pattern. >> comparison with ldp:manages proposal. >> >> >>> I'm hoping this will help the discussion moving forward as it is relevant >>> to all the issues that we have on our agenda for Monday: >>> >>> ISSUE-84 ldp:member >>> ISSUE-85 membershipXXX rules >>> ISSUE-86 "membership triples" misnamed >>> ISSUE-89 Managed resources >>> >>> Regards. >>> -- >>> Arnaud Le Hors - Software Standards Architect - IBM Software Group >> -- >> -ericP >> >> office: +1.617.599.3509 >> mobile: +33.6.80.80.35.59 >> >> (eric@w3.org) >> Feel free to forward this message to any list for any purpose other than >> email address distribution. >> >> There are subtle nuances encoded in font variation and clever layout >> which can only be seen by printing this message on high-clay paper. > Social Web Architect > http://bblfish.net/ > >
Received on Friday, 22 November 2013 22:28:03 UTC