OWLlink Extension:
Retraction HTTP/XML Binding

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.

Status of this Document

This version of the OWLlink retraction specification refers to the public OWL 2 Proposed Recommendation as of 22 September 2009 (http://www.w3.org/TR/2009/PR-owl2-syntax-20090922/) and will be aligned with the Recommendation (which is expected to be published late October).

Please Comment

The OWLlink Working Group seeks public feedback on these Working Drafts. Please send your comments to public-comments@owllink.org or post to the public discussion forum at http://www.owllink.org/forum/.

Set of Documents

This extension is being published as one of a set of 2 documents:

1. Retraction Structural Specification
2. Retraction HTTP/XML Binding (this document)

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-xml-def-20091016.xsd which defines the new Retract element:

  <xsd:schema 
      xmlns:xsd="http://www.w3.org/2001/XMLSchema"
      xmlns:ol="http://www.owllink.org/owllink-xml#"
      targetNamespace="http://www.owllink.org/ext/retraction-xml#"
      elementFormDefault="qualified" attributeFormDefault="unqualified">
  	
      <xsd:import namespace="http://www.owllink.org/owllink-xml#"
                     schemaLocation="http://www.owllink.org/owllink-xml-20091016.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-xml-20091016.xsd which redefines the OWLlink schema underlying the [OWLlink HTP/XML Binding] containing the new element:

  <xsd:schema 
      xmlns:xsd="http://www.w3.org/2001/XMLSchema"
      xmlns:ol="http://www.owllink.org/owllink-xml#"
      xmlns:ext="http://www.owllink.org/ext/retraction-xml#"
      targetNamespace="http://www.owllink.org/owllink-xml#"
      elementFormDefault="qualified" attributeFormDefault="unqualified">
  	       
      <xsd:import namespace="http://www.owllink.org/ext/retraction-xml#"
                     schemaLocation="http://www.owllink.org/ext/retraction-xml-def-20091016.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-xml-20091016.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>
  

The following XML fragment shows a sample application of the retraction extension with an example request message as follows (download as XML file):

<?xml version="1.0" encoding="UTF-8"?>
<RequestMessage xmlns="http://www.owllink.org/owllink-xml#"
    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-xml#"
    xsi:schemaLocation="http://www.owllink.org/owllink-xml#
                        http://www.owllink.org/ext/retraction-xml.xsd">
    <CreateKB kb="http://owllink.org/examples/KB_ext1"/>
    <Tell kb="http://owllink.org/examples/KB_ext1">
        <owl:ClassAssertion>
            <owl:Class IRI="A"/>
            <owl:NamedIndividual IRI="i"/>
        </owl:ClassAssertion>
    </Tell>   
    <ret:Retract kb="http://owllink.org/examples/KB_ext1">
        <owl:ClassAssertion>
            <owl:Class IRI="A"/>
            <owl:NamedIndividual IRI="i"/>
        </owl:ClassAssertion>
    </ret:Retract>
</RequestMessage>

A corresponding server answer could look as follows (download as XML file):

<?xml version="1.0" encoding="UTF-8"?>
<ResponseMessage xmlns="http://www.owllink.org/owllink-xml#"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://www.owllink.org/owllink-xml#
                        http://www.owllink.org/ext/retraction-xml.xsd">
    <KB kb="http://owllink.org/examples/KB_ext1"/>
    <OK/>
    <OK/>
</ResponseMessage>

[OWLlink HTTP/XML Binding]

OWLlink: HTTP/XML Binding. Olaf Noppens, Thorsten Liebig, Marko Luther. Working Group Recommendation, October 2009. http://www.owllink.org/owllink-httpxml-20091016/