When running the Application Server Setup Program you will have to specify how the Database Server that hosts the Application Server Database shall be accessed. This information is used to configure the Application Server's database connection settings.

Usually the Accessing user is created and configured by the the Setup of the Application Server Database (see chapter Step 6: Accessing user in the Database Setup). If not refer to Creating the accessing user.

You can always change the database connection configuration after installation of the Application Server instance by modifying the instance configuration file.