Oracle Database - Database Link

A database link describes how one database instance can log in to another database instance.

A schema object in one database that enables users to access objects on a different database.

SELECT * FROM mySchema.myTable@myDatabaseLink;

CREATE [SHARED] [PUBLIC] DATABASE LINK dblink ... [USING 'net_service_name'];

Oracle Database - Net Service Name (tnsname)

CREATE DATABASE LINK warehouse USING 'warehouse'; 
SELECT DB_LINK FROM USER_DB_LINKS; 

SELECT DISTINCT PRIVILEGE AS "Database Link Privileges"
FROM ROLE_SYS_PRIVS
WHERE PRIVILEGE IN ( 'CREATE SESSION','CREATE DATABASE LINK',
                     'CREATE PUBLIC DATABASE LINK')

Database Link Privileges
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CREATE DATABASE LINK
CREATE PUBLIC DATABASE LINK
CREATE SESSION

• Oracle® Database Administrator's Guide 11g Release 2 (11.2) - Creating database link
• Sql Language Reference - Creating database link