The database has a set of variables that store various system
details about objects, settings, modes, parameters, and so on. Such a variable
is named a system variable. A system variable can be real or virtual.
A real system variable stores its own value in a database container. A virtual
system variable calculates its own value using another object of the database.
The database object has a unified interface for getting and setting
system variables using tagged data technology. The unified interface has
the getSysVar() and setSysVar() methods which require a variable name and use
resbuf-instances for accessing the variable value. Alternatively, the
database object represents the specific methods for some system variables that
automatically convert the variable value to the required data type and do not
require the variable name. Such methods have the names get#() and set#(), where
# is the variable name.