create sequence my_new_sequence nocache;

CREATE TABLE nocache_table(the_id NUMBER)
/

CREATE SEQUENCE nocache_sequence
 START WITH 1 INCREMENT BY 1
NOCACHE
/

DECLARE
  the_number NUMBER;
BEGIN
  -- perform 20 inserts (not all are commited)
  FOR i IN 1..20 LOOP
    SELECT nocache_sequence.NEXTVAL
      INTO the_number
      FROM dual;

    INSERT INTO nocache_table(the_id)
    VALUES ( the_number );

    -- randomly commit or rollback
    IF MOD( 
            ROUND( dbms_random.value(1,4) )
          , 2
          ) = 0
    THEN
      COMMIT;
    ELSE
      ROLLBACK;
    END IF;
  END LOOP;
END;
/

SELECT the_id
  FROM nocache_table
/

DROP SEQUENCE nocache_sequence
/

DROP TABLE nocache_table
/

CREATE TABLE the_table(the_id NUMBER, created_on TIMESTAMP)
/

CREATE VIEW the_view
AS
SELECT ROW_NUMBER() OVER ( ORDER BY created_on ) idx
     , the_id
  FROM the_table
/


CREATE SEQUENCE nocache_sequence
 START WITH 1 INCREMENT BY 1
NOCACHE
/

DECLARE
  the_number NUMBER;
BEGIN
  -- perform 20 inserts (not all are commited)
  FOR i IN 1..20 LOOP
    SELECT nocache_sequence.NEXTVAL
      INTO the_number
      FROM dual;

    INSERT INTO the_table(the_id, created_on)
    VALUES ( the_number, SYSTIMESTAMP );

    -- randomly commit or rollback
    IF MOD( 
            ROUND( dbms_random.value(1,4) )
          , 2
          ) = 0
    THEN
      COMMIT;
    ELSE
      ROLLBACK;
    END IF;
  END LOOP;
END;
/

SELECT the_id
  FROM the_table
/

SELECT idx
     , the_id
  FROM the_view
/

DROP SEQUENCE nocache_sequence
/

DROP view the_view
/

DROP TABLE the_table
/