The Oracle base directory is the database home directory for Oracle Database installation owners. Learn about the Oracle base directory and its naming conventions.

ORACLE_BASE is the root of the Oracle directory tree. If you install an Optimal Flexible Architecture-compliant database using Oracle Universal Installer default settings, then ORACLE_BASE is DRIVE_LETTER:\app\username.

If you are installing Oracle Database for Microsoft Windows on a computer with no other Oracle software installed, then you can change the ORACLE_BASE directory before running Oracle Universal Installer. Most users do not need or want to do this.

Do not change the value of ORACLE_BASE after you run Oracle Universal Installer for the first time. If there is an existing ORACLE_BASE and you change it, then there is a conflict of Oracle base directories. If you create another ORACLE_BASE when the original ORACLE_BASE exists, then certain tools and the database are not able to find previously created files. They look for them in the new ORACLE_BASE instead of the original ORACLE_BASE.

By default, Oracle Universal Installer configures Oracle home directories using these Oracle Optimal Flexible Architecture conventions.

The ORACLE_HOME directory is located under DRIVE_LETTER:\ORACLE_BASE, where DRIVE_LETTER:\is any hard drive, and contains subdirectories for the Oracle software executables and network files.

If you install Oracle Database for Windows on a computer with no other Oracle software installed and you use the default settings, then the first directory that you create is called \dbhome_1.

Oracle Database 11g onwards, Automatic Diagnostic Repository directories replace the bdump, cdump, and udump directories for the database.

The diagnostic data goes into ORACLE_BASE\diag\rdbms\DB_UNIQUE_NAME\instance_name

Some of these subdirectories are:

\alert
\hm
\incident
\incpkg
\ir
\lck
\metadata
\stage
\sweep
\trace

Database administration files are stored in the subdirectories of ORACLE_BASE\admin\DB_UNIQUE_NAME.

Database files are stored in ORACLE_BASE\oradata\DB_UNIQUE_NAME.

Names and brief descriptions of these files are:

CONTROL01.CTL    --control file 1
CONTROL02.CTL    --control file 2
CONTROL03.CTL    --control file 3
EXAMPLE01.DBF    --EXAMPLE tablespace data files
SYSAUX01.DBF     --SYSAUX tablespace data files
SYSTEM01.DBF     --SYSTEM tablespace data file
TEMP01.DBF       --TEMP tablespace data file
USERS01.DBF      --USERS tablespace data file
*.dbf            --data files corresponding to each tablespace in your database
REDO01.LOG       --redo log file group one, member one
REDO02.LOG       --redo log file group two, member one
REDO03.LOG       --redo log file group three, member one

The recovery_area directory stores and manages files related to backup and recovery.

It contains a subdirectory for each database on the system. A fast recovery area is an optional disk location that you can use to store recovery-related files such as control files and online redo log copies, archived logs, flashback logs, and Oracle Database Recovery Manager (RMAN) backups. Oracle and RMAN manage files in the fast recovery area automatically.