Abstract
OWLlink provides a declarative interface for
– among other things –
asserting OWL axioms to a Knowledge Base (KB) of an OWL reasoner.
This OWLlink extension adds the ability to retract previously
asserted axioms from KBs. This document describes the accompanying
HTTP/XML Binding of this extension.
Summary of Changes
Since the latest Working Draft:
- Aligned with the latest OWLlink core and HTTP/XML binding specification
 
Please Comment
The OWLlink Working Group seeks public feedback on this Working
Group Recommendation. Please send your comments to public-comments@owllink.org or post to the public
discussion forum at http://www.owllink.org/forum/.
This extension is being published as one of a set of 4
documents:
- Retraction
Structural Specification
- Retraction
HTTP/XML Binding (this document)
- Retraction
HTTP/Functional Binding
- Retraction
HTTP/S-Expression Binding
1 HTTP/XML Binding
The HTTP/XML binding of this extension follows the guidelines
[OWLlink HTTP/XML
Binding] and consists of the following two
documents:
- http://www.owllink.org/ext/retraction-def-20091116.xsd
which defines the new Retract element:
<?xml version="1.0"
encoding="UTF-8"?>
 <xsd:schema
xmlns:xsd="http://www.w3.org/2001/XMLSchema"
 xmlns:ol="http://www.owllink.org/owllink#"
 targetNamespace="http://www.owllink.org/ext/retraction#"
 elementFormDefault="qualified"
 attributeFormDefault="unqualified">
 
 <xsd:import namespace="http://www.owllink.org/owllink#"
 schemaLocation="http://www.owllink.org/owllink-20091116.xsd"/>
 <xsd:import namespace="http://www.w3.org/XML/1998/namespace"
 schemaLocation="http://www.w3.org/2001/xml.xsd"/>
 
 <xsd:element name="Retract" type="ol:KBRequestWithAxioms"/>
 </xsd:schema>
 
 
 
- http://www.owllink.org/ext/retraction-20091116.xsd
which redefines the OWLlink schema underlying the [OWLlink HTP/XML Binding]
containing the new element:
<?xml version="1.0"
encoding="UTF-8"?>
 <xsd:schema
xmlns:xsd="http://www.w3.org/2001/XMLSchema"
 xmlns:ol="http://www.owllink.org/owllink#"
 xmlns:ext="http://www.owllink.org/ext/retraction#"
 targetNamespace="http://www.owllink.org/owllink#"
 elementFormDefault="qualified"
 attributeFormDefault="unqualified">
 
 <xsd:import namespace="http://www.owllink.org/ext/retraction#"
 schemaLocation="http://www.owllink.org/retraction-def-20091116.xsd"/>
 <xsd:import namespace="http://www.w3.org/XML/1998/namespace"
 schemaLocation="http://www.w3.org/2001/xml.xsd"/>
 
 <xsd:redefine schemaLocation="http://www.owllink.org/owllink-20091116.xsd">
 <xsd:group name="Request">
 <xsd:choice>
 <xsd:group
ref="ol:Request"/>
 <xsd:element
ref="ext:Retract"/>
 </xsd:choice>
 </xsd:group>
 </xsd:redefine>
 </xsd:schema>
 
 
 
2 Example
The following XML fragment shows a sample application of the
retraction extension with an example request message as
follows.
owllink-example-Retraction-request-20091116.xml
<?xml version="1.0"
encoding="UTF-8"?>
<RequestMessage xmlns="http://www.owllink.org/owllink#"
    xml:base="http://www.owllink.org/examples/myOntology#"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:owl="http://www.w3.org/2002/07/owl#"
    xmlns:ret="http://www.owllink.org/ext/retraction#"
    xsi:schemaLocation="http://www.owllink.org/owllink#
      http://www.owllink.org/ext/retraction-20091116.xsd">
    <CreateKB kb="http://www.owllink.org/examples/KB_ext1"/>
    <Tell kb="http://www.owllink.org/examples/KB_ext1">
        <owl:ClassAssertion>
            <owl:Class
IRI="A"/>
            <owl:NamedIndividual
IRI="i"/>
        </owl:ClassAssertion>
    </Tell>
    <GetInstances kb="http://www.owllink.org/examples/KB_ext1"
direct="false">
        <owl:Class IRI="A"/>
    </GetInstances>
    <ret:Retract kb="http://www.owllink.org/examples/KB_ext1">
        <owl:ClassAssertion>
            <owl:Class
IRI="A"/>
            <owl:NamedIndividual
IRI="i"/>
        </owl:ClassAssertion>
    </ret:Retract>
    <GetInstances kb="http://www.owllink.org/examples/KB_ext1"
direct="false">
        <owl:Class IRI="A"/>
    </GetInstances>
    <ReleaseKB kb="http://www.owllink.org/examples/KB_ext1"/>
</RequestMessage>
 
A corresponding server answer could look as follows.
owllink-example-Retraction-response-20091116.xml
<?xml version="1.0"
encoding="UTF-8"?>
<ResponseMessage xmlns="http://www.owllink.org/owllink#"
    xml:base="http://www.owllink.org/examples/myOntology#"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:owl="http://www.w3.org/2002/07/owl#"
    xmlns:ret="http://www.owllink.org/ext/retraction#"
    xsi:schemaLocation="http://www.owllink.org/owllink#
      http://www.owllink.org/ext/retraction-20091116.xsd">
    <KB
kb="http://www.owllink.org/examples/KB_ext1"/>
    <OK/>
    <SetOfIndividualSynsets>
        <IndividualSynset>
            <owl:NamedIndividual
IRI="i"/>
        </IndividualSynset>
    </SetOfIndividualSynsets>
    <OK/>
    <SetOfIndividualSynsets/>
    <OK/>
</ResponseMessage>
 
3 References
- [OWLlink HTTP/XML Binding]
- OWLlink: HTTP/XML Binding Olaf Noppens, Marko Luther, Thorsten Liebig, Michael Wessel. Working Group Recommendation, 16 November 2009, http://www.owllink.org/owllink-httpxml-20091116/. Latest version available at http://www.owllink.org/owllink-httpxml/.