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#2
purana2007-11-23 14:28
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已知关系R1和R2是相容关系,它们各有三个元组和两个元组,则R1和R2进行并运算,其结果的元组数最少有多少个???
希望大家快点回答 急用!!!谢谢
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#2
purana2007-11-23 14:28
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#3
wangch3642002007-11-23 14:47
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#4
orliubc2007-11-23 15:05
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#5
purana2007-11-23 15:21
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#6
XieLi2007-11-23 15:35
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#7
YCqingtian2007-11-23 15:59
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#8
缘吇弹2007-11-23 16:56
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#9
bluebell2007-11-25 23:47
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