When access control is set for some GDB, a list of users having access to this GDB is created. This list can include an arbitrary number of users, but not less than one. An empty list of users denotes unlimited permissions for any user.
For every user his or her name and a password are specified. Both the name and password can be arbitrary not empty strings, user's name is displayed when viewing the list of users, the password is considered to be secret and is never displayed. As a rule, only the user knows his or her own password.
The user which was the first to be added to an empty list of users is GDB administrator. The administrator has all permissions to GDB and his permissions cannot be limited. Some operations (such as GDB reorganization) can be performed only by the administrator if access control is set.
From the point of view of GDB structure users are also considered as GDB components like maps, themes, tables and queries. A list of users is stored on a disk in the structure of GDB. For every user his or her name, password and a set of permissions given to this user are stored.
In mode of shared access to GDB it is not allowed to make any changes in the list of users.
