Making Statements About Containers

You can use a container's ID attribute to make a statement about the container as a whole, separate from the items in the container. Here's an example: In this case, I'm giving a creation date for a Bag container. To do that, I give the Bag container the ID " planets" and then create a new <rdf:Description> element about "#planets" to describe the Bag container and give its date:

Listing ch18_14.rdf

 <?xml version="1.0" ?> <rdf:RDF     xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"     xmlns:dc="http://www.purl.org/DC#">     <rdf:Description         about="http://www.starpowder.com/planets.html">         <dc:Title>XML Links</dc:Title>         <dc:Creator>Nicolas Copernicus</dc:Creator>         <dc:Subject>  <rdf:Bag ID="planets">  <rdf:li                     rdf:resource="http://www.starpowder.com/mercury.html"/>                 <rdf:li                     rdf:resource="http://www.starpowder.com/venus.html"/>                 <rdf:li                     rdf:resource="http://www.starpowder.com/earth.html"/>                 <rdf:li                     rdf:resource="http://www.starpowder.com/mars.html"/>             </rdf:Bag>         </dc:Subject>     </rdf:Description>  <rdf:Description about="#planets">   <dc:Date>   1501-10-15   </dc:Date>   </rdf:Description>  </rdf:RDF>