SQL> 
SQL> -- If "row momement" (alter table enable or disable row momvement) is enabled,
SQL> -- updating a partitioing column may cause rows to change partition and ROWIDs.
SQL> 
SQL> -- insert, delete will not cause row movemnet within hash partitioned table.
SQL> -- but add partition will. Drop, merge and split are not possible with hash at the moment.
SQL> 
SQL> -- Hash partitioning will not equally distribute the data among the partitioins.
SQL> -- Rows of the same hash key value will go to the same partition, of course.
SQL> -- Why not evenly distribute the rows among the partitions and disregard the key values?
SQL> --     Partitioning prunning would not be possible in this case.
SQL> --     Do you get "partition prunning" with hash? Yes, but for equality and IN type
SQL> --                           queries only. Makes sense.
SQL> 
SQL> drop table partest_rowid;
drop table partest_rowid
           *
ERROR at line 1:
ORA-00942: table or view does not exist 


SQL> 
SQL> create table partest_rowid(c1 number(2), c2 varchar2(2))
  2  partition by range (c1)
  3  (partition p1 values less than (10),
  4  partition p2 values less than (20),
  5  partition p3 values less than(maxvalue))
  6  enable row movement;

Table created.

SQL> 
SQL> insert into partest_rowid values(5,'a');

1 row created.

SQL> insert into partest_rowid values(15,'b');

1 row created.

SQL> insert into partest_rowid values(25,'c');

1 row created.

SQL> 
SQL> select rowid, c1, c2 from partest_rowid;

ROWID                      C1 C2                                                
------------------ ---------- --                                                
AAAN5pAAJAAAALIAAA          5 a                                                 
AAAN5qAAJAAAAPgAAA         15 b                                                 
AAAN5rAAJAAAAPwAAA         25 c                                                 

SQL> 
SQL> update partest_rowid set c1=35 where c1=5;

1 row updated.

SQL> 
SQL> -- ROWID of c1=5 changed
SQL> select rowid, c1, c2 from partest_rowid;

ROWID                      C1 C2                                                
------------------ ---------- --                                                
AAAN5qAAJAAAAPgAAA         15 b                                                 
AAAN5rAAJAAAAPwAAA         25 c                                                 
AAAN5rAAJAAAAPwAAB         35 a                                                 

SQL> 
SQL> drop table partest_rowid;

Table dropped.

SQL> 
SQL> create table partest_rowid(c1 number(2), c2 varchar2(2))
  2  partition by hash(c2) partitions 4;

Table created.

SQL> 
SQL> insert into partest_rowid values(1,'a');

1 row created.

SQL> insert into partest_rowid values(2,'b');

1 row created.

SQL> insert into partest_rowid values(3,'c');

1 row created.

SQL> 
SQL> select rowid, c1, c2 from partest_rowid;

ROWID                      C1 C2                                                
------------------ ---------- --                                                
AAAN5tAAJAAAALIAAA          3 c                                                 
AAAN5wAAJAAAAXAAAA          1 a                                                 
AAAN5wAAJAAAAXAAAB          2 b                                                 

SQL> 
SQL> alter table partest_rowid add partition p5;

Table altered.

SQL> 
SQL> -- Some ROWIDs can change when partition is added to the hash-partitioned table
SQL> select rowid, c1, c2 from partest_rowid;

ROWID                      C1 C2                                                
------------------ ---------- --                                                
AAAN5xAAJAAAAXEAAA          3 c                                                 
AAAN5wAAJAAAAXAAAA          1 a                                                 
AAAN5wAAJAAAAXAAAB          2 b                                                 

SQL> 
SQL> drop table partest_rowid;

Table dropped.

SQL> 
SQL> spool off