Question

So I am provided a big XML document. I have to write a query which, given a class name and ontology name, will compute an ontology view which contains the ontology parts of the document which are related to that class. More precisely, I need to select the subclasses of the class, the instances and the rules related to the class. I was thinking of doing this recursively.

Any idea of how can this be done easily?

Answer 1

You can descend the class hierarchy defined in your document via a recursive function:

declare default element namespace "http://omdoc.org/ns";
declare namespace om = "http://www.openmath.org/OpenMath";

declare function local:class-hierarchy(
  $doc as document-node(),
  $classname as xs:string
) as node() {
  <class name='{$classname}'> {
    for $OMA in $doc//axiom/FMP/om:OMOBJ/om:OMA
    where $OMA/om:OMS[1]/@name = 'subclass'
      and $OMA/om:OMS[3]/@name = $classname
    return local:class-hierarchy($doc, $OMA/om:OMS[2]/@name)
  }</class>
};

The function returns nested elements representing the subclass relationships. The subclasses of Device for example can be computed as follows:

let $doc := fn:doc("http://rasdaman.flanche.net/dbwa/Assignment5/example.omdoc"),
    $class := 'Device'
return local:class-hierarchy($doc, $class)

Result:

<class xmlns="http://omdoc.org/ns" name="Device">
  <class name="Camera">
    <class name="DSLR"/>
  </class>
</class>

You can easily adapt this function to return the respective classes’ rules and instances instead.