Authorizations 
After the system has authenticated a user's logon data, a user can, within the scope of his or her authorizations, access data in the database and use database tools.
User types:
Database system administrator (SYSDBA user)
The database system administrator has comprehensive authorizations for access to the database and database tools.
Database user
Database users access data in the database using SQL statements. The database user's user class determines what authorizations he or she has.
DBM operator
DBM operators manage databases. The authorizations of a DBM operator are determined by his or her server authorizations.
Hazards
Data is read by an unauthorized user
A user reads confidential data that should only be visible to a restricted group of users.
Data is changed by an unauthorized user
A user changes data that should only be changed by a restricted group of users.
Activities
More Information
Database Administration, Managing Users