Mamun's DBA Blog: How to create DB Link without modifying the tnsnames.ora

Suppose you want to create a database_link, but you don’t have the privilege to modify the tnsname entry. In that case you can create the database_link directly using tns description.

sql>create public database link DBA connect to orcl identified by welcome1 USING

'(DESCRIPTION=(ADDRESS_LIST=(

ADDRESS=(PROTOCOL=TCP)(HOST=srv1)(PORT=1521)))

(CONNECT_DATA=(SERVICE_NAME=DBA)))'

/

database link created.

Most easiest one is below. No need to write the complete tns description also.

create public database link TEST connect to system identified by welcome1 

 using  '192.168.227.4:1521/TEST';

Database link created.

SQL> select sysdate from dual@TEST;

SYSDATE

---------

13-APR-19