Integers and Datetime literals in RDF XML

Question

I've started to toy around with triplestores and RDF to store image metadata, but I can't understand how to put integer values into RDF/XML.

<?xml version="1.0"?>
<rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:exif="http://penkov.me/exif/">
  <rdf:Description rdf:about="http://penkov.me/images/0">
    <exif:SourceFile>./205CANON/_MG_0538.CR2</exif:SourceFile>
    <exif:Make>Canon</exif:Make>
    <exif:FocalLength>50</exif:FocalLength>
  </rdf:Description>
</rdf:RDF>

I guess 50 in <exif:FocalLength> tag will be treated as a string by a triplestore and it wouldn't be possible to make range queries about this value.

Answer 1

Easy (but verbose):

<exif:FocalLength rdf:datatype="http://www.w3.org/2001/XMLSchema#integer">50</exif:FocalLength>

See this section in the RDF/XML spec