R2RML Blank Node within rr:objectMap

Question

I was wondering how I could model the following with r2rml:

Person -> has an address --> Blank Node [ Street Name, Postal Code, City ]

I'm note sure how I can add street name, postal code and city to the blank node within the rr:objectMap

(Additional question: Is a rr:class mandatory for a rr:BlankNode?)

Any suggestions? :)

<#Person>
    rr:logicalTable [ rr:tableName "PERSON" ];
    rr:subjectMap [
      rr:template "http://ex.com/data/PersonClass/{ID}";
      rr:class ex:PersonClass;
    ];
    rr:preciateObjectMap [
      rr:predicate ex:hasAddress;
      rr:objectMap [
        rr:termType rr:BlankNode;
        ## How/where can a add the street name, postal code, city? ##
      ];
    ].

Answer 1

Should be not too difficult. First you take the R2RML mapping you have created and create a blank node for the address. Give it a unique name by using a template, but do not give it an IRI so it is interpreted as a blank node.

<#Person>
    rr:logicalTable [ rr:tableName "PERSON" ];
    rr:subjectMap [
      rr:template "http://ex.com/data/PersonClass/{ID}";
      rr:class ex:PersonClass;
    ];
    rr:preciateObjectMap [
      rr:predicate ex:hasAddress;
      rr:objectMap [
        rr:template "BlankAddressNode{ADDRESSID}"; 
        rr:termType rr:BlankNode;
      ];
    ].

Note: ADDRESSID in table PERSON is considered a foreign to the primary key of ADDRESS table.

Next you create the blank node with rdf:type and everything else.

<#Address>
    rr:logicalTable [ rr:tableName "ADDRESS" ];
    rr:subjectMap [
      rr:template "BlankAddressNode{ID}"; 
      rr:termType rr:BlankNode;
      rr:class ex:AddressClass;
    ];
    rr:predicateObjectMap [
        rr:predicate    ex:street;
        rr:objectMap    [  rr:column "Street"]
    ];
    .

Note: ID is primary key of ADDRESS table.

You can do this with a join too... but I think from a tutorial point of view this is clearer.