DB_UNIQUE_NAME specifies a globally unique name for the database.

Property Description

Parameter type



DB_UNIQUE_NAME = database_unique_name

Default value

Database instances: the value of DB_NAME

Oracle Automatic Storage Management instances: +ASM



Modifiable in a PDB




Oracle RAC

Multiple instances must have the same value.

Databases with the same DB_NAME within the same DB_DOMAIN (for example, copies of a database created for reporting or a physical standby) must have a unique DB_UNIQUE_NAME. Every database's DB_UNIQUE_NAME must be unique within the enterprise.

The value of DB_UNIQUE_NAME can be up to 30 characters and is case insensitive. The following characters are valid in a database name: alphanumeric characters, underscore (_), number sign (#), and dollar sign ($).


DB_UNIQUE_NAME is used by several components within an Oracle instance to default file names or file paths, such as the default for the DG_BROKER_CONFIG_FILEn initialization parameter. In these cases, on UNIX platforms, the dollar sign ($) character will be removed from the path or file name, because the character is used by Oracle to define the start of an environment variable substitution within a path or file name.


As part of their operations, some database tools or utilities create a string that uniquely identifies a database. The string may include the DB_UNIQUE_NAME for a database, and other identifying information for the database, such as the database SID. Oracle Database restricts some identifiers to 30 characters, so using a short DB_UNIQUE_NAME can help prevent ORA-00972 "identifier is too long" messages from database tools and utilities that create a string that includes the DB_UNIQUE_NAME.

See Also:

Oracle Data Guard Concepts and Administration and Oracle Database Administrator’s Guide for more information on setting this parameter