Linked Data Platform#

Containers#

https://www.w3.org/TR/ldp/#ldpc

We extend the notion of LDP containers!

Terms:

  • Containment Triples

  • Membership Triples

Types:

  • Direct Containers

@prefix dcterms: <http://purl.org/dc/terms/>.
@prefix ldp: <http://www.w3.org/ns/ldp#>.

<http://example.org/c1/>
   a ldp:BasicContainer;
   dcterms:title "A very simple container";
   ldp:contains <r1>, <r2>, <r3>.

  • Indirect Containers - a way of interacting with existing data

Given:

@prefix ldp: <http://www.w3.org/ns/ldp#>.
@prefix o: <http://example.org/ontology#>.

<http://example.org/netWorth/nw1/>
   a o:NetWorth;
   o:netWorthOf <http://example.org/users/JohnZSmith>;
   o:asset 
      <assets/a1>,
      <assets/a2>;
   o:liability 
      <liabilities/l1>,
      <liabilities/l2>,
      <liabilities/l3>.

we can make direct containers that describe the assets and liabilities as containers without modifying the original data

@prefix ldp: <http://www.w3.org/ns/ldp#>.
@prefix dcterms: <http://purl.org/dc/terms/>.
@prefix o: <http://example.org/ontology#>.

<http://example.org/netWorth/nw1/assets/>
   a ldp:DirectContainer;
   dcterms:title "The assets of JohnZSmith";
   ldp:membershipResource <http://example.org/netWorth/nw1/>;
   ldp:hasMemberRelation o:asset;
   ldp:contains <a1>, <a2>.

Additionally, if one were to add a new set of “advisors,” we would make an indirect container that tells us we need an additional triple when creating new members of the container (foaf:primaryTopic):

<advisors/>
   a ldp:IndirectContainer;
   dcterms:title "The asset advisors of JohnZSmith";
   ldp:membershipResource <>;
   ldp:hasMemberRelation o:advisor;
   ldp:insertedContentRelation foaf:primaryTopic;
   ldp:contains
   	 <advisors/bob>,     # URI of a document a.k.a. an information resource
   	 <advisors/marsha>.  # describing a person

(still unclear to me what is different about that, still reading.)

Completed Request

Membership Effect

Containment Effect

Create in Basic Container

New triple: (LDPC, ldp:contains, LDPR)

Same

Create in Direct Container

New triple links LDP-RS to created LDPR. LDP-RS URI may be same as LDP-DC

New triple: (LDPC, ldp:contains, LDPR)

Create in Indirect Container

New triple links LDP-RS to content indicated URI

New triple: (LDPC, ldp:contains, LDPR)

Resource deleted

Membership triple may be removed

(LDPC, ldp:contains, LDPR) triple is removed

Container deleted

Triples and member resources may be removed

Triples of form (LDPC, ldp:contains, LDPR) and contained LDPRs may be removed

Similarities#

  • Separation between container data and metadata - “minimal-container triples,” what remains in the container when the container has zero members and zero contained resources

Differences#

  • Containers are not recursive??or at least that is suggested by the ‘net worth’ example that explains why we can’t just turn the original subject into a container: “can’t mix assets and liabilities” and i am like why not make one container for the person and then subcontainers for each of the types?

References#