ISNULL

The ISNULL function is used to determine whether a DOM handle is null. It is commonly used to check for null values in return results from interfaces such as GETFIRSTCHILD, GETDOCUMENTELEMENT, and MAKENODE.

Syntax

DBMS_XMLDOM.isNull (
   n IN DBMS_XMLDOM.DOMNODE);

DBMS_XMLDOM.isNull (
   doc IN DBMS_XMLDOM.DOMDOCUMENT);

DBMS_XMLDOM.isNull (
   elem IN DBMS_XMLDOM.DOMELEMENT);

DBMS_XMLDOM.isNull (
   text IN DBMS_XMLDOM.DOMTEXT);

DBMS_XMLDOM.isNull (
   attr IN DBMS_XMLDOM.DOMATTR);

DBMS_XMLDOM.isNull (
   character_data IN DBMS_XMLDOM.DOMCHARACTERDATA);

Parameters

Return value

If the handle is null, TRUE is returned; otherwise, FALSE is returned.

Usage instructions

The different overloads accept various DOM handles; it is recommended to call this function first to check for null values before proceeding to access the node.

Examples

DECLARE
  n       DBMS_XMLDOM.DOMNODE;
  is_null BOOLEAN;
BEGIN
  is_null := DBMS_XMLDOM.isNull(n);
END;
/