How to activate a database link?

Question

How can one activate a database link w/in SQL*Plus or DBA Studio?
I'm trying to re-create my schema in a new instance and in order to execute my materialized view SQL I must first create a new database link. I'm using the same info as in our other instance so am sure the connection will work IF I can get the database link to be 'active'. I created the link in DBA Studio and attempted to test, but received the error "Database link is not active." Canned it and created through SQL*Plus with same result. I see no option to activate and cannot find any info in 8i DBA Handbook or 8i DBA Bible.
Only way to create an active dblink is to find another link that is already active and do a Create Like.
I figure there's an easy solution to this problem, but cannot figure out what it is. Any help is appreciated!
Thanks.

Answer 1

Nathan,
What is the exact sql your using to create the link? Sometimes I've seen OEM say the link is not active when its a private one (the pressing of the TEST button that is). Maybe it's a bug or something (I just tested it now again to make sure I was getting the db link test error). This is with OEM 1.6x though, I thought it would have been fixed by the current version. Maybe it never was a bug I don't know.
I norammly create and activate a db link like this ...
DROP DATABASE LINK DB_TEST;
CREATE PUBLIC DATABASE LINK DB_TEST CONNECT TO <user> IDENTIFIED BY <pass> USING '<tns name entry on the SERVER>;
SELECT NAME FROM V$DATABASE@DB_TEST;
Here's an actual run and gets the databsae name off the linked server ...
15:42:59 ORACLE [->] CREATE DATABASE LINK DB_TEST_PRIVATE CONNECT TO USER1 IDENTIFIED BY
USER1 USING 'TNS1';
Database link created.
15:42:59 ORACLE [->] CREATE PUBLIC DATABASE LINK DB_TEST_PUBLIC CONNECT TO USER1 IDENTIFI
ED BY USER1 USING 'TNS1';
Database link created.
15:42:59 ORACLE [->] SELECT NAME AS "LINK_PRIVATE" FROM V$DATABASE@DB_TEST_PRIVATE;
LINK_PRIV
DEVL
15:43:00 ORACLE [->] SELECT NAME AS "LINK_PUBLIC" FROM V$DATABASE@DB_TEST_PUBLIC;
LINK_PUBL
DEVL
The following link tells more about database links and some good examples ...
http://otn.oracle.com/docs/products/oracle9i/doc_library/901_doc/server.901/a90117/ds_admin.htm#12904
The folowwing is from that page on checking on current open db links ...
--[START]
You may find it useful to determine which database link connections are currently open in your session. Note that if you connect as SYSDBA, you cannot query a
view to determine all the links open for all sessions; you can only access the link information in the session within which you are working.
The following views show the database link connections that are currently open in your current session:
V$DBLINK (view) : Lists all open database links in your session, that is, all database links with the IN_TRANSACTION column set to YES.
GV$DBLINK (view) : Lists all open database links in your session along with their corresponding instances. This view is useful in an Oracle Real Application Clusters
configuration.
--[END]
Sometimes the v$dblink doesn't show all the active ones (since it might have gotton opened under a different user name or something), but doing a simple select * from dual@DB_LINK, will most certainly open it if the connection is not yet open. Creating the databse link itself does not open the actuall connection.
Hope this helps ya,
Tyler D.