Covered indexes enhance performance when all fields requested by a query are contained within the covered index because there is no need to pull up the full document record.

Covered索引在查询所请求的全部字段都包含在Covered索引中时能提升性能，因为不再需要取出完整的文档记录。

youdao

Why does the fossil record not document the series of evolutionary changes during the evolution of animals?

为什么化石记录没有记录动物进化过程中的一系列进化变化？

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The states hold the necessary information for tracking where the parser is in reading the document; the edges record the progress from one state to the next.

状态保留跟踪解析器读取文档时处在位置所需的必要信息；边记录了从一种状态到下一种状态的进展。

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Hasseen is also accused of possessing a document or record containing information that may have been useful to a person preparing to perform a terrorism act on 3 July.

BBC: EDL: Terror suspects deny attack plan

Yet the work is more than simply a record or document as Wicks explains.

BBC: They are Us and We are Them

Prosecutor Ken Karas read the document into the court record Tuesday morning.

CNN: Witness backtracks at embassy bombings trial