OMF (Oracle Managed Files) in oracle is used to simplify creation of database files as Oracle does all OS operations and file naming. It helps:
· Automatic cleanup of the filesystem when database objects are dropped.
· Standardized naming of database files.
· Increased portability since file specifications are not needed.
· Simplified creation of test systems on differing operating systems.
· No unused files wasting disk space.
The location of database files is defined using the DB_CREATE_FILE_DEST parameter
ALTER SYSTEM SET DB_CREATE_FILE_DEST=’D:\oracle\oradata\testdata\OMF\’;
Files typically have a default size of 100M and are named using the following formats where u% is a unique 8 digit code, g% is the logfile group number,
and %t is the tablespace name:
Redo Log Files
Create tablespace test_omf;
The resultant datafiles will have a default size of 100M and AUTOEXTEND
CREATE TABLESPACE test_omf DATAFILE SIZE 150M;
ALTER TABLESPACE test_omf ADD DATAFILE;
DROP TABLESPACE test_omf