Interroger le type de données Oracle Clob

J'espère que cet exemple illustre clairement ce que j'essaie d'expliquer.

SET SQLBL ON;
SET DEFINE OFF;

CREATE TABLE CLOB_TEST
(
clob_in CLOB
);

INSERT
INTO CLOB_TEST VALUES
  (
    'I am working as a DBA and senior database resource in L&T Infotech in Pune India'
  );


SELECT DBMS_LOB.SUBSTR(CLOB_IN,3000) ot FROM CLOB_TEST;

-----------------------------OUTPUT------------------------------------------

OT
I am working as a DBA and senior database resource in L&T Infotech in Pune India

-----------------------------OUTPUT------------------------------------------