XSD Import to use foaf in the XSL-Schema

Question

extending an rdf-vocabulary like FOAF is possible using XML-Schema but how can I use classes from such a vocabulary inside the definition? Basically I want to add new elements to the foaf:person and I want to make sure, that having those elements means that this object is a foaf:Person and nothing else.

<?xml version="1.0" encoding="UTF-8"?>
 <xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" targetNamespace="http://www.example.org/NewXMLSchema" xmlns:foaf="http://xmlns.com/foaf/0.1/" elementFormDefault="qualified">

<xs:import foaf:namespace="http://xmlns.com/foaf/0.1/" foaf:schemaLocation="http://xmlns.com/foaf/spec/index.rdf"/>

<xs:complexType ref="foaf:Person">
    <xs:sequence>
        <xs:element name="owns">
            <xs:complexType>
                <xs:sequence>
                    <xs:element name="device">
                        <xs:complexType>
                            <xs:sequence>
                                <xs:element name="HereBeSomething"></xs:element>
                            </xs:sequence>
                        </xs:complexType>   
                    </xs:element>
                </xs:sequence>
            </xs:complexType>
        </xs:element>
        <xs:element name="datapoints">
            <xs:complexType>
                <xs:sequence>
                    <xs:element name="point" type="xs:string"></xs:element>
                </xs:sequence>
            </xs:complexType>
        </xs:element>
    </xs:sequence>
</xs:complexType>

the Complex Type is supposed t be the foaf:Person, but this arangement results in an errror:

"Multiple annotations found at this line: - s4s-att-must-appear: Attribute 'name' must appear in element 'complexType'. - s4s-att-not-allowed: Attribute 'ref' cannot appear in element 'complexType'."

How can I use Types from other RDF-Ontologies in the definition of my new Schema?

score 2 · Answer 1 · answered Jul 27 '11 at 09:07

I would not go there. XML Schema isn't really a good tool for dealing with RDF data. Many people look at RDF's XML serialization and think, “oh so it's just like XML with some extra rdf:this and rdf:that attributes thrown in.” But that's deceptive.

RDF is a set of subject-predicate-object triples. There are multiple syntaxes for writing these triples down into files. RDF/XML is one of them; Turtle and N-Triples and RDFa are others.

The problem with RDF/XML is that there are many different ways of writing down the same set of triples in an RDF/XML file. For example, the following two snippets are exactly equivalent:

<foaf:Person rdf:about="#cygri">
    <foaf:nick>cygri</foaf:nick>
</foaf:Person>

<rdf:Description rdf:ID="cygri">
    <rdf:type rdf:resource="http://xmlns.com/foaf/0.1/Person">
    <foaf:nick>cygri</foaf:nick>
</foaf:Person>

In summary: My recommendation is not to use XML tools to process RDF data. Use RDF tools. To extend an RDF Schema like FOAF, use RDF Schema.

XSD Import to use foaf in the XSL-Schema

1 Answers1