Dynamically call DBMS_XMLINDEX to drop parameter and exit with exception

Question

Hi All,
I am trying to create a procedure to dynamically call DBMS_XMLINDEX.dropparameter.
If the parameter does not exist then gracefully exit with exception as 'Parameter does not exist'.
But I keep on getting errors due to dynamically passing.
Procedure is something like:
Create PROCEDURE drop_parameter(p_parameter IN VARCHAR2)
IS
no_parameter EXCEPTION;
PRAGMA EXCEPTION_INIT(no_parameter,-12004);
BEGIN
EXECUTE IMMEDIATE 'DBMS_XMLINDEX.dropparameter( ''||p_parameter||'') ';
dbms_output.put_line('Parameter dropped');
EXCEPTION
WHEN no_parameter THEN
dbms_output.put_line('Parameter does not exist');
END drop_parameter;
For implementaion we can try creating parameter as :
BEGIN
DBMS_XMLINDEX.REGISTERPARAMETER (
'Param1',
'PATH TABLE PathTB1
PATHS (INCLUDE ( /a/b/c
/d/e/f
END;
The above parameter should be dropped or if not existing, then exit gracefully.
Please suggest.
Thanks...

Answer 1

You're testing the wrong error code...
ORA-12004 : http://docs.oracle.com/cd/E11882_01/server.112/e17766/e9858.htm#sthref3299
Try with ORA-44737, for example :
SQL> set serveroutput on
SQL>
SQL> BEGIN
  2  DBMS_XMLINDEX.REGISTERPARAMETER (
  3  'Param1', 'PATH TABLE PathTB1 PATHS (INCLUDE ( /a/b/c /d/e/f ))');
  4  END;
  5  /
PL/SQL procedure successfully completed
SQL>
SQL> CREATE PROCEDURE drop_parameter(p_parameter IN VARCHAR2)
  2  IS
  3    no_parameter EXCEPTION;
  4    PRAGMA EXCEPTION_INIT(no_parameter,-44737);
  5  BEGIN
  6    DBMS_XMLINDEX.dropparameter(p_parameter);
  7    dbms_output.put_line('Parameter dropped');
  8  EXCEPTION
  9    WHEN no_parameter THEN
10        dbms_output.put_line('Parameter does not exist');
11  END;
12  /
Procedure created
SQL> exec drop_parameter('Param1');
Parameter dropped
PL/SQL procedure successfully completed
SQL> exec drop_parameter('Param1');
Parameter does not exist
PL/SQL procedure successfully completed
(and again, you do not need dynamic code)