There are 25 Levels of Message in an Oracle Forms.
How much cretical error or message is
0 -- all errors or message
1
2
.
.
.
25 -- don't shows any

If we don't wannat show any error or message to the user then we assign 25 to message level as
:SYSTEM.MESSAGE_LEVEL : 25;

Now system will not show any message error to the user.

If i wanna show all the errors then assign it 0.
:SYSTEM.MESSAGE_LEVEL : 0;