We work with SQL Server 2008 R2. I am attaching a screenshot with the [Microsoft SQL Server Management Studio] window to illustrate the problem.
I have created a linked server via ODBC DSN to Oracle database. The name of this linked server is ORACLE_DB, and you can see it in the list of linked servers in the left pane.
Connection test fine, and I can see all the tables in Oracle database if I expand that node.
When I execute the sp_helpserver, though, ORACLE_DB is not listed, as you can see in the Results pane. Another linked server I have (PRDDX5600) is visible both in treeview and in the results of execution of sp_helpserver.
When I try to execute a query using the ORACLE_DB linked server, I get an error "Could not find server 'ORACLE_DB' in sys.servers."
I hope I am missing something simple. I'd appreciate if anybody could push me in the right direction.