instance method change_column

# File activerecord/lib/active_record/connection_adapters/mysql2_adapter.rb, line 513
      def change_column(table_name, column_name, type, options = {})
        column = column_for(table_name, column_name)

        unless options_include_default?(options)
          options[:default] = column.default
        end

        unless options.has_key?(:null)
          options[:null] = column.null
        end

        change_column_sql = "ALTER TABLE #{quote_table_name(table_name)} CHANGE #{quote_column_name(column_name)} #{quote_column_name(column_name)} #{type_to_sql(type, options[:limit], options[:precision], options[:scale])}"
        add_column_options!(change_column_sql, options)
        add_column_position!(change_column_sql, options)
        execute(change_column_sql)
      end