In the following statements about functional dependency, which one is incorrect?

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问题 In the following statements about functional dependency, which one is incorrect?

选项 A、If

then X→X’.
B、If X→Y and

then X→Y’.
C、If X→Y and

then X’→Y.
D、If X→Y and Y→Z, then X→Z.

答案C

解析
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