通常，您将存储标题字段，但不是身体领域，处理相当大的文件时，你会添加一个标识符字段(索引)，可用于检索实际的文档。

Typically, you would store the title fields, but not the body fields, when handling largish documents, and you'd add an identifier field (not indexed) that can be used to retrieve the actual document.

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第一个字段是每个记录都必须使用的唯一ID标识符。

The first field is the highly desirable unique id identifier for each record.

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将标识符指定为一个字段属性，让图表知道使用哪个值来创建大小适合的楔形饼图。

Specify the identifier as a field property so that the chart knows which value to use to create pie wedges of the appropriate size.

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