how to change directory of (rename) datafiles in oracle 9.2

shutdown the instance. copy the datafiles to the place you desire.

mount the  database  with sys user

SQL> startup mount;
ORACLE instance started.

Total System Global Area 1075808408 bytes
Fixed Size                   731288 bytes
Variable Size             738197504 bytes
Database Buffers          335544320 bytes
Redo Buffers                1335296 bytes
Database mounted.

SQL> alter database rename file '/izmir2/oradb/dbf01.dbf' to
  2  '/izmir1/oradb/dbf01.dbf';

Database altered.

Rename each datafile by using the command above with your directory and datafile names

 

If you  want to make  sure that the db is pointing to the new place you can rename your datafiles at operating system level

 

then

alter database open

and its done!