Name         Null?    Type
------------ -------- ----------------------------
 USRNM                 VARCHAR2(15) UNIQUE
 PASWD        NOT NULL VARCHAR2(15)
 STATUS                CHAR(1)
---------------------------------------------------

USRNM           PASWD           S
--------------- --------------- -
TEST            TEST            Y
ADMIN           ADMIN           N

DECLARE 
	A VARCHAR2(15);
	B VARCHAR2(15);
	C CHAR(1);
BEGIN

	SELECT USRN,PASWD,STATUS INTO A,B,C FROM LOGON
	WHERE USRNM=:LOGON.USRNM;
	IF A=:USRNM AND B=:PASWD AND  C='N' THEN --->(I WANNA TO CHECK HERE THE STATUS OF THE TABLE AND UPDATE THE TABLE TO 'Y')
           UPDATE LOGON SET STATUS='Y' WHERE USRNM=A;
           COMMIT_FORM;
 	   Message('You have no unsaved changes outstanding.'); 
 	   CALL_FORM(GETPATH||'MAIN_MENU',HIDE); --> (IF SESSION IS TRUE THEN CALL MAIN_MENU)

	   CLEAR_RECORD;
	   RAISE FORM_TRIGGER_FAILURE;
	ELSIF C='Y' THEN
		MESSAGE('You have already logged on at another Machine !!!!');
		ELSE
		MESSAGE('Invalid Password or Username !!!');
		GO_ITEM('LOGON.USRNM');
	END IF;
	--	END IF;
	EXCEPTION
		WHEN NO_DATA_FOUND THEN 
		MESSAGE('Invalid Username or Password!!!');
END;