单选

●ER模型可以转换成关系模型。当两个实体间联系是M∶N联系时，它通常可转换成 (27) 个关系模式。
(27)

A．2 &n
bsp; B．3
C．M+N
D．M-N

试题出自试卷《2011年程序员考试考前密卷（六）-上午试题》

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●ER模型可以转换成关系模型。当两个实体间联系是M∶N联系时，它通常可转换成 (27) 个关系模式。(27)

●ER模型可以转换成关系模型。当两个实体间联系是M∶N联系时，它通常可转换成 (27) 个关系模式。
(27)