There are few commands that can be used to display existing databases on the system:
Help user <username>
This command is used to display the names of all the Tables (T), Views (V), Macros (M), and Triggers (G) stored in a user area and table comments.
User creation is somewhat similar to database creation. A user needs to be in a certain hierarchy to fulfill its existence. When the system is installed, DBC, systemfe, and sysadmin are default users that are created on the system. All the space is given to DBC, which sits at top of the hierarchy:
