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下列关于E-R图的叙述中,哪些是正确的?

A、E-R图用于描述数据的逻辑模型
B、E-R图提供了表示实体型、属性和联系的方法
C、属性用菱形表示,并用无向边将其与相应的实体连接起来
D、联系也可以有属性
E、实体型用矩形表示,矩形框内写明实体名
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正确答案:

BDE

答案解析:

暂无解析

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