CREATE OR REPLACE TRIGGER s_trigger
BEFORE UPDATE OR INSERT OR DELETE ON employee
FOR EACH ROW
BEGIN
  IF inserting OR updating('salary') THEN
    IF :NEW.salary < 0 THEN
      DBMS_OUTPUT.PUT_LINE('THE SALARY CANNOT BE NEGATIVE');
    ELSIF :NEW.salary > 6000 THEN
      DBMS_OUTPUT.PUT_LINE('THE SALARY CANNOT EXCEED 6000');
    END IF;
  END IF;
END;
/

Object: nil error: did not understand #OR
MessageNotUnderstood(Exception)>>signal (ExcHandling.st:254)
UndefinedObject(Object)>>doesNotUnderstand: #OR (SysExcept.st:1448)
UndefinedObject>>executeStatements (prog:1)
Object: 'salary' error: did not understand #THEN
MessageNotUnderstood(Exception)>>signal (ExcHandling.st:254)
String(Object)>>doesNotUnderstand: #THEN (SysExcept.st:1448)
UndefinedObject>>executeStatements (prog:5)

./prog:6: expected expression