“年龄在18～25之间”这种约束是属于数据库当中的( )。
A．原子性措施
B．一致性措施
C．完整性措施
D．安全性措施
参考答案：C
—May I speak to Mr. Li?
—Sorry. He isn’t in now. He somewhere abroad since last Friday.
A．has been
B．has been to
C．has gone to
D．has been in
炸药是指？
