Compare Longs

I need to compare the database value of a LONG with a new value.

Is there any way of telling if they are different, as I only want to update the row if they are different.

As in...

   update table

      set field1=new_field1,
          longfield=new_longfield,
          dirty='Y'
     where field1<>new_field1
       and longfield<>new_longfield;