Sets a value of a parameter.
The value can be set at either the session or the global level.
Setting at session level is valid only during the current session's lifetime; setting at global level is persistent and affects the entire system by becoming the default value for all new sessions.
If set level is not specified, session level is assumed.
Hierarchy of the parameters value levels (top override lower levels):
- Session level setting
- Local setting (through the local-conf.ini file)
- Global level setting
- Default value