关系数据库的规范化理论指出：关系数据库中的关系应满足一定的要求，最起码的要求是达到1NF，即满足( )。
A．每个非码属性都完全依赖于主码属性
B．主码属性惟一标识关系中的元组
C．关系中的元组不可重复
D．每个属性都是不可分解的
参考答案：D
解析： 1NF的要求是每个属性都是不可分解的：2NF的要求是每个非码属性都完全依赖于主码属性：3NF的要求是每个非码属性都直接依赖于主码属性。
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