No Host information in dba_db_links

Question

I'm auditing the db_links in some databases and have found a number of db_links with no host information. I checked the sys.LINK$ table and there is no host info there either. The database links are all called LINK followed by a timestamp. Has anyone encountered this before?

SELECT OWNER#,NAME,HOST FROM SYS.LINK$ WHERE OWNER#=234 AND NAME = 'LINK20111011104440086446000';

OWNER# NAME                           HOST

---

   234 LINK20111011104440086446000

Answer 1

That link is not valid. Oracle will let you create a link with no information: create database link testlink will work, but without a using clause it doesn't do anything, it's incomplete and not yet a functioning link. If you attempt to use it, select * from dual@testlink you will get "ORA-02019: connection description for remote database not found"

You should probably drop that link.