在SQL Server 2000中,有商品表(商品号,商品名,单价)和销售表(商品号,销售时间,销售价格)。现要限制“销售价格”的取值必须在此商品“单价”的0.6~1.5倍范围之内,实现这个约束的正确代码是______。 A)CHECK(销售价格BETWEEN单价×0.6 AND单价×1.5) B)CHECK(销售价格BETWEEN商品表.单价×0.6 AND商品表.单价×1.5) C)CREATE TRIGGER tri_Sales ON销售表FOR INSERT,UPDATE AS IF EXISTS(SELECT * FROM INSERTED a JOIN商品表b ON a.商品号=b.商品号 WHERE销售价格NOT BETWEEN单价×0.6 AND单价×1.5) ROLLBACK D)CREATE TRIGGER tri_Sales ON销售表 INSTEAD OF INSERT,UPDATE AS IF EXISTS(SELECT×FROM INSERTED a JOIN商品表b ON a.商品号=b.商品号 WHERE销售价格NOT BETWEEN单价×0.6 AND单价×1.5) ROLLBACK