The SYSDBA user (database system administrator) is a special database user of the database user class SYSDBA. The SYSDBA user is the first database user that the Database Manager creates when a new database instance is installed. Enter a user name and password for this user.
When you enter the data for the SYSDBA user and when you use it in the SQL environment, remember that the Database Manager automatically converts all characters into uppercase.
Each database instance has a single SYSDBA user.
The SYSDBA user’s password can be changed once the database registration is complete (for example, using the query tool SQL Studio).
The SYSDBA user is very important, especially when database instances are installed. The SYSDBA user is responsible for setting up the system and for creating other database users. The SYSDBA user is the owner of system tables. When system tables are uploaded, the upload tool logs on to the database instance as SYSDBA.
The SYSDBA is able to define data and database procedures. The SYSDBA can also grant other users privileges for these database objects.