A database link that links each database in a network to all other databases. This enables any user of any database in the network to specify a global object name in a SQL statement or object definition. An Oracle Names server can store global database links.

A global database link that is the same as the global database name is automatically registered with the Oracle Names server.
For example, if the global database name is sales.us.acme.com, a global link with the same name is registered with the Oracle Names server. You verify a global database link is working correctly by performing a SELECT statement on a table, for example:
SQL> SELECT * from [email protected]

Unless you want to specify user name and password credentials for a global database link, no additional configuration is required to use the global database link.

To define a user name and password for a global database link, use either Net8 Assistant or the NAMESCTL control utility. Because the NAMESCTL utility is limited in global database link registration functionality, Oracle Corporation recommends you use Net8 Assistant.