/**
  * @param QOM\ChildNodeInterface $constraint
  *
  * @return string
  */
 public function walkChildNodeConstraint(QOM\ChildNodeInterface $constraint)
 {
     return $this->getTableAlias($constraint->getSelectorName()) . ".parent = '" . $constraint->getParentPath() . "'";
 }
 private function walkChildNodeConstraint(QOM\ChildNodeInterface $constraint)
 {
     $selectorName = $constraint->getSelectorName();
     $path = $constraint->getParentPath();
     return sprintf('%s:%s', $this->escape(ZendSearchAdapter::IDX_PARENTPATH), $path);
 }