在Access 2000中可以定义三种类型的主键是______主键、单字段主键和多字段主键。

在Access 2000中可以定义三种类型的主键是______主键、单字段主键和多字段主键。

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下列叙述中,错误的是( )

下列叙述中,错误的是( )A.更新查询一次可以更新多个字段的值B.删除查询可以从多个表中删除记录C.使用追加查询追加的记录,可以用“撤销”命令恢复所做的更改D.利用子查询的结果可以进行进一步的查询

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排除;消灭 v. e_ _ _ _ _ _ _ _

排除;消灭 v. e_ _ _ _ _ _ _ _

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What is known about the influenza virus?

What is known about the influenza virus?A. It was first found in a group of very old birds.B. All the

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Passage TwoQuestions 26 to 30 are based on the following passage. Scientists hav

Passage TwoQuestions 26 to 30 are based on the following passage.Scientists have established that inf

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