Identifying Databases

The Oracle Database software identifies a database by its global database name.

A global database name consists of the database name and database domain. Usually, the database domain is the same as the network domain, but it need not be. The global database name uniquely distinguishes a database from any other database in the same network. You specify the global database name when you create a database during the installation, or when using Oracle Database Configuration Assistant.

The database name input field is used to set the DB_NAME, DB_UNIQUE_NAME, and DB_DOMAIN Oracle initialization parameter values.

For example:

sales_world.example.com

In this example:

sales_world 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 ASCII alphanumeric, underscore (_), dollar ($), and pound (#) characters but must begin with an alphabetic character. No other special characters are permitted in a database name.
sales_wo is the DB_NAME. The DB_NAME initialization parameter specifies a database identifier of up to eight characters.
example.com is the network domain in which the database is located. Together, the database name and the network domain make the global database name unique. The domain portion is a string of no more than 128 characters that can contain alphanumeric, underscore (_), and pound (#) characters. The DB_DOMAIN initialization parameter specifies the 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.

For example, if the SID and database name for an Oracle database are ORCL, then each database file is located in the ORACLE_BASE\oradata\orcl directory, and the initialization response file is located in the ORACLE_BASE\admin\orcl\pfile directory.