instance method attributes_from_column_definition

# File activerecord/lib/active_record/locking/optimistic.rb, line 61
        def attributes_from_column_definition
          result = super

          # If the locking column has no default value set,
          # start the lock version at zero.  Note we can't use
          # locking_enabled? at this point as @attributes may
          # not have been initialized yet

          if lock_optimistically && result.include?(self.class.locking_column)
            result[self.class.locking_column] ||= 0
          end

          return result
        end