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关系模式R分解成数据库模式ρ的一个缺点是()。

单选题
2022-03-16 01:29
A、存储悬挂元组
B、减少了数据冗余
C、查询时,需要做连接运算
D、数据分散存储在多个关系中
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正确答案
C

试题解析

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