- From: Richard Cyganiak <richard@cyganiak.de>
- Date: Wed, 25 Jul 2012 17:59:45 +0100
- To: Tomasz Pluskiewicz <tomasz.pluskiewicz@gmail.com>
- Cc: Juan Sequeda <juanfederico@gmail.com>, David McNeil <dmcneil@revelytix.com>, public-rdb2rdf-comments@w3.org
On 25 Jul 2012, at 15:05, Tomasz Pluskiewicz wrote: > Sorry to revive an old topic, but I have recenlty realized the root of > my question. > > The R2RML specs at http://www.w3.org/TR/r2rml/#dfn-term-map state > clearly that "A term map must be exactly one of the following: a > constant-valued term map, a column-valued term map, a template-valued > term map." Doesn't this mean that a term map > > <StudentsTriplesMap> rr:subjectMap > [ > rr:termType rr:BlankNode; > rr:class <http://example.com/Student> > ]; > > is in fact invalid, having no explicit rr:constant, rr:column or > rr:template property? It is indeed invalid. You'd usually want an rr:template or rr:column that creates the blank node identifier. Best, Richard > > Regards, > Tomasz > > On Fri, Jun 8, 2012 at 10:19 PM, Tomasz Pluskiewicz > <tomasz.pluskiewicz@gmail.com> wrote: >> Thank you for answering. Also, let me answer here again. >> >> I forgot to mention I intended the mapping as default mapping for >> table without primary key. >> >> In my oppinion by default direct mapping should generate a blank node >> for each row. And I do have mixed feelings about the behavior not >> preserving duplicate rows. >> >> Regards, >> Tomasz >> >> On Fri, Jun 8, 2012 at 6:26 PM, Juan Sequeda <juanfederico@gmail.com> wrote: >>> I asked on the forum, but let me ask here. >>> >>> are you expecting the R2RML engine to generate a blank node for each tuple, >>> or do you have a column value that you would like to use in order to >>> generate the blank node? >>> >>> Juan Sequeda >>> +1-575-SEQ-UEDA >>> www.juansequeda.com >>> >>> >>> >>> On Fri, Jun 8, 2012 at 9:22 AM, David McNeil <dmcneil@revelytix.com> wrote: >>>> >>>>> From the latest R2RML draft: >>>> >>>> * a subject map is a term map, >>>> http://www.w3.org/2001/sw/rdb2rdf/r2rml/#dfn-term-map >>>> >>>> * the termType property can be used on term maps, >>>> http://www.w3.org/2001/sw/rdb2rdf/r2rml/#termtype >>>> >>>> So "yes", you can use termType on subject maps and this is how you would >>>> produce subjects as blank nodes. >>>> >>>> -David >>> >>> >
Received on Wednesday, 25 July 2012 17:00:42 UTC