Call now: 252-767-6166  
Oracle Training Oracle Support Development Oracle Apps

 E-mail Us
 Oracle Articles

 Oracle Training
 Oracle Tips

 Oracle Forum
 Class Catalog

 Remote DBA
 Oracle Tuning
 Emergency 911
 RAC Support
 Apps Support
 Oracle Support

 SQL Tuning

 Oracle UNIX
 Oracle Linux
 Remote s
 Remote plans
 Application Server

 Oracle Forms
 Oracle Portal
 App Upgrades
 SQL Server
 Oracle Concepts
 Software Support

 Remote S


 Consulting Staff
 Consulting Prices
 Help Wanted!


 Oracle Posters
 Oracle Books

 Oracle Scripts

Don Burleson Blog 







Create a database link Tips

Oracle Tips by Burleson Consulting
January 17, 2008

Question:  How to create a database link in Oracle?  What are the options for creating database links?

Answer:  Oracle has invested heavily in distributed database technology and the creation of a database link is very straightforward.  You specify the database link name, the remote user to connect to, the password for the remote user and the TNS service name for the database link connection:

create public database link
connect to
identified by
using 'tns_service_name';

Starting in 11g release 2, the syntax has been enhanced to remove the need to epscify a TNS service_name:

create public database link
connect to
identified by
using 'myserver:1521/MYSID';

Above we see that the TNS instance name has been replaced by allowing the server name, port number and Oracle system ID (ORACLE_SID).

You can also create a database link to non-Oracle databases,  Francisco Riccio describes the steps for a database link to MySQL:

Step 1:  Your first step is having installed the TRANSPARENT GATEWAY (it comes in as of the options when you install Oracle).

Step 2: You must have a user in the SQL Server.

Step 3: In the directory <ORACLE_HOME>\tg4msql\admin look for the file inittg4msql.ora and have the following options:


Step 4: Configure the listener and add the following

(PROGRAM = tg4msql)
(ORACLE_HOME = C:\oracle1)

and in our tnsnames.ora add

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

where HS set up as a heterogonous service

Step 5: create a link to sql server.

create database link msql connect to user_sqlserver identified by password using 'MSQL';

Step 6: You can now use the database link to a foreign database:

select * from table@msql

For more information on database links, see my related notes below:

Fix a broken Oracle db link

How to create an Oracle database link

Oracle Database Links tnsnames.ora tns_admin global_names Replication

Oracle Database Links global_name Replication

Oracle Database Links Basic Replication Repadmin Schema

Oracle Database Links Enterprise Manager Replication


Get Complete Oracle Tuning Details 

The landmark book "Oracle Tuning: The Definitive Reference Third Edition" has been updated with over 800 pages of expert performance tuning tips. It's packed with scripts and tools to hypercharge Oracle performance and you can buy it for 40% off directly from the publisher.





oracle dba poster

Oracle performance tuning software 
Oracle Linux poster


Burleson is the American Team

Note: This Oracle documentation was created as a support and Oracle training reference for use by our DBA performance tuning consulting professionals.  Feel free to ask questions on our Oracle forum.

Verify experience! Anyone considering using the services of an Oracle support expert should independently investigate their credentials and experience, and not rely on advertisements and self-proclaimed expertise. All legitimate Oracle experts publish their Oracle qualifications.

Errata?  Oracle technology is changing and we strive to update our BC Oracle support information.  If you find an error or have a suggestion for improving our content, we would appreciate your feedback.  Just  e-mail:  and include the URL for the page.


Burleson Consulting

The Oracle of Database Support

Oracle Performance Tuning

Remote DBA Services


Copyright ? 1996 -  2014

All rights reserved by Burleson

Oracle ? is the registered trademark of Oracle Corporation.