attributes_from_column_definition

# File activerecord/lib/active_record/locking/optimistic.rb, line 68
        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
          # <tt>locking_enabled?</tt> at this point as
          # <tt>@attributes</tt> may not have been initialized yet.

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

          result
        end