PLSQL中INDEX BY TABLE的 DELETE操作

--INDEX BY Table
SET SERVEROUTPUT ON;

DECLARE
  TYPE enm_tab_type IS TABLE OF
       emp.ename%TYPE
       INDEX BY BINARY_INTEGER;
  
  enm_table enm_tab_type;
BEGIN
  enm_table(1):='1001';
  enm_table(2):='1002';
  enm_table(3):='1003';
  enm_table(4):='1004';
  enm_table(6):='1006';

  enm_table.DELETE(5);
  IF enm_table.EXISTS(6) THEN
     dbms_output.put_line('exists(6)');
  ELSE
     dbms_output.put_line('not exists(6)');
  END IF;
  
END;
/

anonymous block completed
exists(6)