问题 填空题

在Visual FoxPro中,建立数据库表时,将年龄字段值限制在18~45岁之间的这种约束属于()完整性约束。

答案

参考答案:

解析:

[知识点] 域完整性

[评析] 数据类型的定义都属于域完整性的范畴。如对于数值型字段,通过指定不同的宽度说明不同范围的数值数据类型,从而可以限定字段的取值类型和取值范围。但这些对域完整性还远远不够,我们还可以用一些域约束规则来进一步保证域完整性。

单项选择题
填空题

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