Procedure:

1. Log in to the SMS from a client.
2. On the SMS toolbar, navigate to the Admin->Database tab.
3. In the External Database Settings section, click Edit. The Edit External Database Settings dialog box opens.
4. From the navigation pane, click External Access Settings.
5. Check the Enable external database access checkbox to grant external access and uncheck the box to disable access.
6. If enabling access, enter the username and password of a database user with sufficient rights to read all the desired data from the SMS database.
7. After ensuring all SMS clients have logged off the SMS Server, click Reboot to complete the task of changing the external access setting.

Reference: SMS User Guide