The duration datatype specified in the XML Schema 1.0 Datatypes Recommendation (see Resources) is a partially orderedtype that represents a period of time.
XML Schema 1.0 Datatypes Recommendation（参见 参考资料）中指定的 duration 数据类型是一个半序类型（partially ordered type），表示一个时间段。
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SHIPPED item information (SHIPPEDORDER) : This table contains shipping ID, Customer ID, type of box ordered, number ordered, and date ordered.