A database link (DB link) in Oracle is a way to connect to and access data from another database. It allows you to query and manipulate data from the remote database as if it were local. DB links are useful for data integration, sharing, and consolidation.
There are several ways to check if a DB link is working properly. One way is to use the SQL Plus DESCRIBE command. This command will display information about the DB link, including its status, type, and connection parameters.