含有消息发送人标识符的属性。类型是字节数组。

Property containing the sender identifier of the message. The type is an array of bytes.

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相反，它只需要程序员将属性标记为持久性的，并识别出能代表对象唯一标识符(或者主键)的属性。

Instead, it requires the developer only to denote the attributes to be persisted and to identify the attribute to represent the object's unique identifier (or primary key).

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名称空间是元素或属性的标识符的一部分。

A namespace is a part of the identifier for an element or attribute.

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