SQL> select  banner
  2    from  v$version
  3  /

BANNER
--------------------------------------------------------------------------------
Oracle Database 12c Enterprise Edition Release 12.1.0.1.0 - 64bit Production
PL/SQL Release 12.1.0.1.0 - Production
CORE    12.1.0.1.0      Production
TNS for 64-bit Windows: Version 12.1.0.1.0 - Production
NLSRTL Version 12.1.0.1.0 - Production

SQL> create table tbl(ename varchar2(20))
  2  /

Table created.

SQL> alter table tbl
  2    add constraint tbl_pk
  3      primary key(ename)
  4  /

Table altered.

SQL> create materialized view log on tbl
  2  /

Materialized view log created.

SQL> create materialized view tbl_mv
  2    refresh fast
  3    on demand
  4    as
  5      select  *
  6        from  tbl
  7  /

Materialized view created.

SQL> insert
  2    into tbl
  3    select  ename
  4      from  emp
  5  /

14 rows created.

SQL> commit
  2  /

Commit complete.

SQL> exec dbms_mview.refresh('tbl_mv','f');

PL/SQL procedure successfully completed.

SQL> alter table tbl
  2    add job varchar2(20)
  3  /

Table altered.

SQL> exec dbms_mview.refresh('tbl_mv','f');

PL/SQL procedure successfully completed.

SQL> update tbl
  2     set job = (select job from emp where emp.ename = tbl.ename)
  3  /

14 rows updated.

SQL> commit
  2  /

Commit complete.

SQL> exec dbms_mview.refresh('tbl_mv','f');

PL/SQL procedure successfully completed.

SQL> select  *
  2    from  tbl_mv
  3  /

ENAME
--------------------
ADAMS
ALLEN
BLAKE
CLARK
FORD
JAMES
JONES
KING
MARTIN
MILLER
SCOTT

ENAME
--------------------
SMITH
TURNER
WARD

14 rows selected.

SQL>

SQL> alter table tbl
  2    add sal number
  3  /

Table altered.

SQL> drop materialized view log on tbl
  2  /

Materialized view log dropped.

SQL> create materialized view log on tbl
  2  /

Materialized view log created.

SQL> exec dbms_mview.refresh('tbl_mv','f');
BEGIN dbms_mview.refresh('tbl_mv','f'); END;

*
ERROR at line 1:
ORA-12034: materialized view log on "SCOTT"."TBL" younger than last refresh
ORA-06512: at "SYS.DBMS_SNAPSHOT", line 2802
ORA-06512: at "SYS.DBMS_SNAPSHOT", line 3039
ORA-06512: at "SYS.DBMS_SNAPSHOT", line 2998
ORA-06512: at line 1


SQL>