• 2022-06-07
    为表ReaderType的LimitNum字段添加检查约束,要求教该字段的值<3,正确的语句是
    A: ALTER TABLE ReaderTypeADD CONSTRAINT CK_ReaderType_LimitNum check (LimitNum=3)
    B: ALTER TABLE ReaderTypeADD CONSTRAINT check (LimitNum<3)
    C: ALTER TABLE ReaderTypeADD CONSTRAINT CK_ReaderType_LimitNum (LimitNum<3)
    D: ALTER TABLE ReaderTypeADD CONSTRAINT CK_ReaderType_LimitNum check (LimitNum<3)
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