Example 10-16 Using the DBMS_WARNING Package to Display Warnings

-- When warnings disabled, the following procedure compiles with no warnings
CREATE OR REPLACE PROCEDURE unreachable_code AS
  x CONSTANT BOOLEAN := TRUE;
BEGIN
  IF x THEN
    DBMS_OUTPUT.PUT_LINE('TRUE');
  ELSE
    DBMS_OUTPUT.PUT_LINE('FALSE');
  END IF;
END unreachable_code;
/
-- enable all warning messages for this session
CALL DBMS_WARNING.set_warning_setting_string('ENABLE:ALL' ,'SESSION');
-- Check the current warning setting
SELECT DBMS_WARNING.get_warning_setting_string() FROM DUAL;

-- Recompile the procedure and a warning about unreachable code displays
ALTER PROCEDURE unreachable_code COMPILE;
SHOW ERRORS;