|Default value||There is no default value.|
|Range of values||Any legal string of name components, separated by periods and up to 128 characters long (including the periods). This value cannot be
|Real Application Clusters||You must set this parameter for every instance, and multiple instances must have the same value.|
In a distributed database system,
DB_DOMAIN specifies the logical location of the database within the network structure. You should set this parameter if this database is or ever will be part of a distributed system. The value consists of the extension components of a global database name, consisting of valid identifiers (any alphanumeric ASCII characters), separated by periods. Oracle recommends that you specify
DB_DOMAIN as a unique string for all databases in a domain.
This parameter allows one department to create a database without worrying that it might have the same name as a database created by another department. If one sales department's
JAPAN.ACME.COM, then their
SALES database (
SALES.JAPAN.ACME.COM) is uniquely distinguished from another database with
SALES but with
If you omit the domains from the name of a database link, Oracle expands the name by qualifying the database with the domain of your local database as it currently exists in the data dictionary, and then stores the link name in the data dictionary. The characters valid in a database domain name are: alphanumeric characters, underscore (_), and number sign (#).