问题 单项选择题

第(37)~(38)题基于“学生-选课-课程”数据库中的3个关系:
S(S#,SNAME,SEX,AGE),
SC(S#,C#,GRADE),
C(C#, CNAME, TEACHER)

若要求查找姓名中第二个字为“阳”字的学生的学号和姓名,下列SQL语句中,( )
是正确的。
Ⅰ、SELECT S#,SNAME FROM S WHERE SNAME=’_阳%’
Ⅱ、SELECT S#,SNAME FRQM S WHERE SNAME LIKE’_阳%’
Ⅲ、SELECT S#,SNAME FROM S WHERE SNAME LIKE’%阳%’

A.只有Ⅰ

B.只有Ⅱ

C.只有Ⅲ

D.都正确

答案

参考答案:B

解析: 这是一个LIKE查询,LIKE谓语一般形式是:
列名LIKE字符串常数
这里,列名的数据类型必须是字符型。在字符串常数中字符的含意如下:
①字符_(下划线)表示可以和任意的单个字符匹配。
②字符%(百分号)表示可以和任意长的字符串匹配。
题意要求查找第二个字为“阳”的学生学号和姓名,所以查询条件应该是’_阳%’,所以B)选项是正确的。

填空题
单项选择题 案例分析题

From childhood to old age, we all use language as a means of broadening our knowledge of ourselves and the world about us. When humans first 1 , they were like newborn children, unable to use this 2 tool. Yet once language developed, the possibilities for human kind’s future 3 and cultural growth increased.

Many linguists believe that evolution is 4 for our ability to produce and use language. They 5 that our highly evolved brain provides us 6 an innate language ability not found in lower 7 . Proponents of this innateness theory say that our 8 for language is inborn, but that language itself develops gradually, 9 a function of the growth of the brain during childhood. Therefore there are critical 10 times for language development.

Current 11 of innateness theory are mixed, however, evidence supporting the existence of some innate abilities is undeniable. 12 , more and more schools are discovering that foreign languages are best taught in 13 grades. Young children often can learn several languages by being 14 to them, while adults have a much harder time learning another language once the 15 of their first language have become firmly fixed.

16 some aspects of language are undeniably innate, language does not develop automatically in a vacuum. Children who have been 17 from other human beings do not possess language. This demonstrates that 18 with other human beings is necessary for proper language development. Some linguists believe that this is even more basic to human language 19 than any innate capacities. These theorists view language as imitative, learned behavior. 20 , children learn language from their parents by imitating them. Parents gradually shape their child's language skills by positively reinforcing precise imitations and negatively reinforcing imprecise ones.

请在13处填上正确答案()

A.various

B.different

C.the higher

D.thelower