For example:

sales.us.example.com

Here:

• sales.us is the name of the database. The database name, DB_UNIQUE_NAME, portion is a string of no more than 30 characters that can contain alphanumeric characters, underscore (_), dollar sign ($), and pound sign (#) but must begin with an alphabetic character. No other special characters are permitted in a database name.

• sales.us is also the DB_NAME. The DB_NAME initialization parameter specifies a database identifier of up to eight characters.

• example.com is the database domain in which the database is located. In this example, the database domain equals the network domain. Together, the database name and the database domain make the global database name unique. The domain portion is a string of no more than 128 characters that can contain alphanumeric characters, underscore (_), and pound sign (#). The DB_DOMAIN initialization parameter specifies the database domain name.

However, the DB_NAME parameter need not necessarily be the first eight characters of DB_UNIQUE_NAME.

The DB_UNIQUE_NAME parameter and the DB_DOMAIN name parameter combine to create the global database name value assigned to the SERVICE_NAMES parameter in the initialization parameter file.

The system identifier (SID) identifies a specific database instance. The SID uniquely distinguishes the instance from any other instance on the same computer. Each database instance requires a unique SID and database name. In most cases, the SID equals the database name portion of the global database name.