How to extract ddl for oracle db links? - oracle

Question

Is there anyway to extract ddl for all database links?
I would like to get in sql and recreate them via sql.
I can use below and it works for PUBLIC user but for non public user it doesn't give me db link owner.
Set long 1000
SELECT DBMS_METADATA.GET_DDL('DB_LINK',db.db_link,db.owner) from dba_db_links db;
Sample link owner and name
Owner db_link
public link1
public link2
user1 link3
If I ran above select it will give me below, #3 doesn't have username in it.
Output from above SELECT
1. create public database link "link1" using "db_alias"
2. create public database link "link2" using "db_alias"
3. create database link "link3" using "db_alias"
I recreate links using SYS and don't want to create #3 as SYS user.

Answer 1

Seems that even as SYS user you can't easity create dblink for another user (except of public dblink).
Even if you run create database link your_user.link3 using "db_alias" it's owner will be SYS.
Possible hacks are connect as another user (you may add conn into SQL*Plus script if you have credentials)
Or create procedure for user that need to have dblink that run create database link command with parameters and call it from sys.

Answer 2

this should help with links that do a "connect to"
SELECT MYCOMMAND
FROM
(
select trim(l.owner)||'__'||trim(l.db_link)||'__'||trim(l.username) ||'__'||trim(l.host) , '10'
, ' connect '||trim(l.owner)||'/CCCCCCCC#'||TRIM(INSTANCE_NAME)
AS MYCOMMAND
from dba_db_links l , V$INSTANCE i , dba_users u
where l.username = u.username
and l.username is not null
and l.username <> ' '
UNION ALL
select trim(l.owner)||'__'||trim(l.db_link)||'__'||trim(l.username)||'__'||trim(l.host) , '20'
, ' DROP DATABASE LINK '||trim(l.db_link)||' ; ' AS MYCOMMAND
from dba_db_links l , V$INSTANCE i , dba_users u
where l.username = u.username
and l.username is not null
and l.username <> ' '
UNION ALL
select trim(l.owner)||'__'||trim(l.db_link)||'__'||trim(l.username)||'__'||trim(l.host) , '30'
, ' CREATE DATABASE LINK '||trim(l.db_link)
||' CONNECT TO "'||trim(l.username)||'"'
||' IDENTIFIED BY "NNNNNNNN" '
||' USING '||trim(l.host) ||' ; 'AS MYCOMMAND
from dba_db_links l , V$INSTANCE i , dba_users u
where l.username = u.username
and l.username is not null
and l.username <> ' '
ORDER BY 1,2,3
)

Answer 3

To get ddl from db links, run the output of the command below:
set pages 999;
set long 90000;
SELECT 'SELECT dbms_metadata.get_ddl(''DB_LINK'',''' || db_link || ''',''' || owner || ''') FROM dual;'
FROM dba_db_links
WHERE db_link
IN ('DB_LINK1',
'DB_LINK2',
'DB_LINK3');
For create a db link for other user, with user SYS execute the DDL below:
CREATE DATABASE LINK "OWNER.DBLINK_NAME"
CONNECT TO "USER" IDENTIFIED BY "Password_user"
USING 'ALIAS';