When you install an Oracle Database Optimal Flexible Architecture-compliant database, there is a top-level Oracle base directory, DRIVE_LETTER: \app\username, where DRIVE_LETTER is the hard drive letter.

The Oracle base directory contains \ORACLE_HOME directories, \oradata directories (for database files), \diag (for diagnostic data), \flash_recovery_area (for recovery operations), and \admin directories (for database administration files).

Database files do not have the SID in the database file name.

For example, the first control file is named control01.ctl. The SID in the file name is not necessary because all the database files for a particular database are placed in \oradata under a directory called DB_UNIQUE_NAME that is named for that database.

In an Optimal Flexible Architecture-compliant release, database file names have the following extensions:

• .ctl for control files

• .log for log files

• .dbf for data files