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倍到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) 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
Questions 59-60 are based on the following information A hash table With hash function H1(k)=k mod 13 Is shown below. Collision is resolved using the hash function H2(k)=(k mod 11)+1 How many key comparisons occur in searching for key 35 in the given hash table?
What is the contra positive of the relation represented in the exhibit shown below?
A. R= {<1,2>,< 1,3>,<1,4>,<1,5>} B. R= {< 1,1>,<2,2>,<3,3>,<4,4>,<5,5>} C. R= {<2,1 >,<4,1>,<2,2>,<1,3>,<3,2>,<1,4>,<4,4>,<5,4>} D. R= {<1,2>,<3,1>,<1,4>,<2,2>,<2,3>,<4,1>,<4,4>,<4,5>}