In the cases when a group of users work with one and the same GDB it may be quite useful to control user permissions, that is, determine for each user what he or she has the right to do and what he or she cannot do depending on user's qualification, competence and the tasks set before the user.
ObjectLand includes tools allowing for specifying if a particular user has the right to work with the present GDB, which components of this GDB are accessible for him and what operations with data he or she can perform. Besides, it is possible to set which users have the right to make changes in the shared style library.
Possibilities of working with GDB provided for a particular user including the possibility to know about the presence of these or those GDB components, view and change the structure of components and the data belonging to them are called user's permissions with respect to the present GDB.
Control of access to GDB gives a possibility to form sets of permissions for particular users in a very flexible way. Several possibilities can be enumerated as examples.
It is possible to grant access only to table data or on the contrary, only to maps for the user.
It is possible to indicate a list of tables and maps accessible for the user having revoked access to other tables and maps for him.
It is possible to disable changing of data for the user, giving access only for viewing.
It is possible to enable changing of data but disable changing of structure of GDB components.
There is a possibility to disable the user to perform such analytical operations as sorting, search and calculations in tables.
It is possible to grant access to maps and tables only via particular themes and queries thus making some layers and features types of the map and table fields inaccessible for the user.
It is possible to disable changing displayed fragment having provided the user with some limited part of the map for work.
It is possible to disable changing style library providing the user with a possibility to use only existing styles.
The possibility to change user permissions also requires a special permission which can be granted to one or several competent users.
Apart from GDB ObjectLand also works with such an important structure of data as shared style library. Permissions to this library should be determined separately since the shared library is not a part of GDB. The only permission to shared library in ObjectLand which can be given not to all users is permission to edit the library.
Using tools of access control when working with ObjectLand is not compulsory. There is no need to use these tools if only one person has physical access to the computer on which the system is installed or if high discipline and competence of all members of the group exclude the possibility of unauthorized operations. Nevertheless, in many situations access control can be a useful accessory tool complementing organizational measures on regulation of working with the system.
It should be noted that the possibilities of control of user access to such actions as removing and copying GDB and system library entirely depend on the operating system used. Such a limitation is impossible for Windows 95/98, however it can be implemented when Windows 2000/XP is used.
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