Searching semantically tagged documents in MarkLogic

Question

Can any one please point me to some simple examples of semantic tagging and querying semantically tagged documents in MarkLogic?

I am fairly new in this area,so some beginner level examples will do.

Answer 1

When you say "semantically tagged" do you mean regular XML documents that happen to have some triples in them? The discussion and examples at http://docs.marklogic.com/guide/semantics/embedded are pretty good for that.

Start by enabling the triple index in your database. Then insert a test doc. This is just XML, but the sem:triple element represents a semantic fact.

xdmp:document-insert(
  'test.xml',
  <test>
    <source>AP Newswire</source>
    <sem:triple date="1972-02-21" confidence="100">
      <sem:subject>http://example.org/news/Nixon</sem:subject>
      <sem:predicate>http://example.org/wentTo</sem:predicate>
      <sem:object>China</sem:object>
    </sem:triple>
  </test>)

Then query it. The example query is pretty complicated. To understand what's going on I'd insert variations on that sample document, using different URIs instead of just test.xml, and see how the various query terms match up. Try using just the SPARQL component, without the extra cts query. Try cts:search with no SPARQL, just the cts:query.

xquery version "1.0-ml";
import module namespace sem = "http://marklogic.com/semantics" 
  at "/MarkLogic/semantics.xqy";
sem:sparql('
  SELECT ?country
  WHERE {
<http://example.org/news/Nixon> <http://example.org/wentTo> ?country
  }
  ',
 (),
 (),
 cts:and-query((
   cts:path-range-query( "//sem:triple/@confidence", ">", 80) ,
   cts:path-range-query( "//sem:triple/@date", "<",     xs:date("1974-01-01")),
   cts:or-query((
     cts:element-value-query( xs:QName("source"), "AP Newswire"),
     cts:element-value-query( xs:QName("source"), "BBC"))))))