SQL>

SQL> create or replace directory bla as '/home/oracle';

Directory created.

SQL>

SQL> create table db_table(col01 varchar2(100));

Table created.

SQL>

SQL> CREATE TABLE ext_table (col01 varchar2(100))

  2  ORGANIZATION EXTERNAL

  3  (

  4  TYPE oracle_loader

  5  DEFAULT DIRECTORY bla

  6  ACCESS PARAMETERS

  7  (RECORDS DELIMITED BY NEWLINE)

  8  LOCATION ('x.dat')

  9  )

 10  REJECT LIMIT UNLIMITED;

Table created.

SQL>

SQL> select * from db_table;

no rows selected

SQL> exec  execute immediate 'insert into db_table select * from ext_table EXTERNAL MODIFY (LOCATION (:new_location))' using 'a.dat';

PL/SQL procedure successfully completed.

SQL> select * from db_table;

COL01

--------------------------------------------------------------------------------

i was in a.dat

SQL> rollback;

Rollback complete.

SQL> exec execute immediate 'insert into db_table select * from ext_table EXTERNAL MODIFY (LOCATION (:new_location))' using 'b.dat';

PL/SQL procedure successfully completed.

SQL> select * from db_table;

COL01

--------------------------------------------------------------------------------

i was in b.dat

SQL> rollback;

Rollback complete.

SQL>

SQL> exit

Disconnected from Oracle Database 12c Enterprise Edition Release 12.2.0.1.0 - 64bit Production