Hi Pantelis, You have to combine the recipes
“Example: Property bridge using information from another database table” “Example: Joining a table to itself using d2rq:alias” from the manual at http://www4.wiwiss.fu-berlin.de/bizer/d2rq/spec/ Note in particular the use of d2rq:alias. Hope that helps, Richard On 10 Mar 2011, at 18:16, Pantelis N. Karamolegkos wrote: > Hi, > > I am using the attached MySQL db schema. > I want to add a property bridge to the Person Class (derived from the Person > table) that will list the persons that each person has interacted with (i.e. > the pairings of each person in the TracesOfContacts table). > > I added the following section in the mapping file but it does not seem to > work (I don’t even see the property InteractsWith appearing in the web > browser), although it does appear in the respective rdf dump > <http://localhost:2020/vocab/resource/person_InteractsWith> > <http://www.w3.org/2000/01/rdf-schema#label> "Has Interacted With the > following" . > <http://localhost:2020/vocab/resource/person_InteractsWith> > <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> > <http://www.w3.org/1999/02/22-rdf-syntax-ns#Property> . > > > I have also used the (now in comment) sql statement (after also commenting > the d2rq:column "person.ID"; statement) but I get the following error message > Subquery returns more than 1 row: SELECT DISTINCT `person`.`ID`, (SELECT > `tracesofcontacts`.`PersonB` from tracesofcontacts, person WHERE > `tracesofcontacts`.`PersonA` = `person`.`ID`) AS expr9eb38d53 FROM > `tracesofcontacts`, `person` (E0) > > > > Any ideas? > > Thanx, > > > map:person_InteractsWith a d2rq:PropertyBridge; > d2rq:belongsToClassMap map:person; > d2rq:property vocab:person_InteractsWith; > d2rq:column "person.ID"; > #d2rq:sqlExpression "SELECT tracesofcontacts.PersonB from > tracesofcontacts, person WHERE tracesofcontacts.PersonA = person.ID"; > d2rq:join "tracesofcontacts.PersonA => person.ID"; > d2rq:join "tracesofcontacts.PersonB <= person.ID"; > d2rq:datatype xsd:integer; > d2rq:propertyDefinitionLabel "Has Interacted With the > following"; > <test_db.pdf>------------------------------------------------------------------------------ > Colocation vs. Managed Hosting > A question and answer guide to determining the best fit > for your organization - today and in the future. > http://p.sf.net/sfu/internap-sfd2d_______________________________________________ > d2rq-map-devel mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/d2rq-map-devel ------------------------------------------------------------------------------ Colocation vs. Managed Hosting A question and answer guide to determining the best fit for your organization - today and in the future. http://p.sf.net/sfu/internap-sfd2d _______________________________________________ d2rq-map-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/d2rq-map-devel
