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.