/**
  * Short description of method delete
  *
  * @access public
  * @author Jerome Bogaerts, <*****@*****.**>
  * @param  Resource resource
  * @param  boolean deleteReference
  * @return boolean
  */
 public function delete(core_kernel_classes_Resource $resource, $deleteReference = false)
 {
     $returnValue = (bool) false;
     //delete all values of the property to delete
     if ($deleteReference) {
         $query = 'DELETE FROM "statements" WHERE "predicate" = ? AND ' . $this->getModelWriteSqlCondition();
         $returnValue = $this->getPersistence()->exec($query, array($resource->getUri()));
     }
     $returnValue = parent::delete($resource, $deleteReference);
     return (bool) $returnValue;
 }