Oracle PL/SQL/Large Objects/EMPTY BLOB

difference between EMPTY_BLOB() & EMPTY_CLOB() and NULL

 
SQL>
SQL> CREATE TABLE lobdemo (
  2    key NUMBER,
  3    clob_col CLOB,
  4    blob_col BLOB);
Table created.
SQL>
SQL>
SQL> INSERT INTO lobdemo (key, blob_col, clob_col)
  2    VALUES (80, EMPTY_BLOB(), EMPTY_CLOB());
1 row created.
SQL>
SQL> INSERT INTO lobdemo (key, blob_col, clob_col)
  2    VALUES (81, NULL, NULL);
1 row created.
SQL>
SQL> drop table lobdemo;
Table dropped.
SQL>