The XML Ontology Backend allows users to save a Protégé ontology in XML format. Ontology classes are read out as types in an XML Schema and ontology instances are read out in an XML document instance. Please see the documentation section for a more detailed description of the output of this back-end.

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To install: Put the xmlontologybackend.jar in the <protege_home>/plugins/ directory and restart Protégé.

To run: Open a project and go to Project -> Save In Format... -> XML Ontology Schema. Since we're just putting this plug-in into use, we highly recommend that you save the XML version of your ontology in a directory other than your current project directory, as it will overwrite your current PPRJ file.

Last updated: January 12, 2004

This back-end generates three files:

base.xsd: Defines data common to all Protégé projects
<project_name>.xsd: Contains ontology class definitions
<project_name>.xml: Defines four sections of data, which are slots, own slot values, slot overrides, and instances in sequence. XML elements are defined in alphabetical order in each section. Sections are separated by XML element SEPARATORs.

Class names that contain special characters are encoded. The encoding of special characters is as follows:

< ==> __lt

> ==> __gt

& ==> __amp

" ==> __quot

' ==> __apos

+ ==> __plus

: ==> __colon

/ ==> __slash

, ==> __comma

( ==> __lprent

) ==> __rprent

To save projects that include other projects, you will need to save the included projects in XML Ontology format first.

Besides dividing sections in XML files (described above in <project_name>.xml description), SEPARATORs are also used in definitions of subclasses. It separates ownslot definitions from template slot definitions.