Copia

4Suite repository Document Definitions can now support both XML and text-based serialization of RDF. Document Definitions essentially facilitate database replication of XML to RDF (within a content management system that persists both). The mechanism is similar to transactional data replication in database management systems where modifications to a table triggers the replication. Previously, they were only expected to output to RDF/XML - which has well-known issues.

Now, the repository persistence driver attempts to parse the resulting RDF syntax based on the XSLT output method. This allows for a hueristic to prospectively attempt to accomodate non-XML syntax (such as Notation 3 - the only substantial RDF text-based syntax) as well as RDF/XML (and even TriX).

The main advantage for these syntax alternatives is a faster, more efficient parse time in addition to more human readable syntax (especially for data that was meant to be expressed in this way). This switching off the xsl:output method is analagous to switching off HTTP header content-type values for remote RDF graphs (where the parsing is also a bottleneck).

Ofcourse, 4Suite's aging RDF library doesn't properly perist N3 formulae (which are logic syntactic sugar specific to Notation 3) from the parser it uses.

Imagine using a Document Definition to, say, replicate SWRL's XML syntax into Notation 3's implication syntax for a logic programming database:

if x1 hasParent x2, x2 hasSibling x3, and x3 hasSex male, then x1 hasUncle x3

SWRL Rule

<ruleml:imp> 
  <ruleml:_rlab ruleml:href="#example1"/>
  <ruleml:_body> 
    <swrlx:individualPropertyAtom  swrlx:property="hasParent"> 
      <ruleml:var>x1</ruleml:var>
      <ruleml:var>x2</ruleml:var>
    </swrlx:individualPropertyAtom> 
    <swrlx:individualPropertyAtom  swrlx:property="hasBrother"> 
      <ruleml:var>x2</ruleml:var>
      <ruleml:var>x3</ruleml:var>
    </swrlx:individualPropertyAtom> 
  </ruleml:_body> 
  <ruleml:_head> 
    <swrlx:individualPropertyAtom  swrlx:property="hasUncle"> 
      <ruleml:var>x1</ruleml:var>
      <ruleml:var>x3</ruleml:var>
    </swrlx:individualPropertyAtom> 
  </ruleml:_head> 
</ruleml:imp>

Notation 3 Rule

{ ?x1 :hasParent ?x2; ?x2 :hasSibling ?x3; ?X3 :hasSex :Male } => { ?x1 :hasUncle ?x3 }.

Now imagine using GRDDL to publish a common set of rules as SWRL, with a profile to transform them to Notation 3 for scutters that understand.

Chimezie Ogbuji