对于学生关系S(S#,SN,AGE,SEX),写一条规则,把其中的AGE属性限制在15~30之间,则这条规则属于______。
A.实体完整性规则
B.参照完整性规则
C.用户定义的完整性规则
D.不属于以上任何一种规则
- · 有3位网友选择 C,占比37.5%
- · 有3位网友选择 D,占比37.5%
- · 有1位网友选择 B,占比12.5%
- · 有1位网友选择 A,占比12.5%
A.实体完整性规则
B.参照完整性规则
C.用户定义的完整性规则
D.不属于以上任何一种规则
假定有3种关系,学生关系S、课程关系C、学生选课关系SC,它们的结构如下:
S(S#(学号) , SN(姓名) , SEX(性别) , AGE(年龄) , DEPT(系别))
C (C#(课程号) , CN(课程名) )
SC (S#(学号) , C#(课程号) , GRADE(成绩) )
其中S# 为学生号,SN为姓名,SEX为性别,AGE为年龄,DEPT为系别,C# 为课程号,CN为课程名,GRADE为成绩。检索所有比“李军”年龄大的学生的姓名、年龄和性别,正确的SQL语句是___ ___。
A: SELECT SN,AGE,SEX
FROM S
WHERE AGE >(SELECT AGE
FROM S
WHERE SN = “李军” )
B: SELECT SN,AGE,SEX
FROM S
WHERE AGE >(SN = “李军”)
C: SELECT SN,AGE,SEX
FROM S
WHERE AGE >(SELECT AGE
WHERE SN=“李军”)
D: SELECT SN,AGE,SEX
FROM S
WHERE AGE>李军.AGE
A.S
B.SC,C
C.S,SC
D.S,C,SC
A、SELECT SN,AGE,SEX FROM S WHERE AGE<(select age from s where sn="王华"> B、SELECT SN,AGE,SEX FROM S WHERE SN='王华'
C、SELECT SN,AGE,SEX FROM S WHERE AGE<(select age where sn="王华"> D、SELECT SN,AGE,SEX FROM S WHERE SGE<王华.age<br>
A.SELECT SN,AGE,SEX FROM S WHERE AGE>(SELECT AGE FROM S WHERE SN=王华)
B.SELECT SN,AGE,SEX FROM S WHERE SN=王华
C.SELECT SN,AGE,SEX FROM S WHERE AGE>(SELECT AGE WHERE SN=王华)
D.SELECT SN,AGE,SEX FROM S WHERE SGE>王华.AGE
有如下3个关系表:
S(S#,SN,SEX,AGE,DEPT)
C(C#,CN)
SC(S#,C#,GRADE)
其中,S#为学号,SN为姓名,SEX为性别,AGE为年龄,DEPT为系别,C#为课程号,
CN为课程名,GRADE为成绩。检索所有比“王华”年龄大的学生的姓名、年龄和性别。
正确的SELECT语句是( )。
A.SELECT SN,AGE,SEX FROM S;
WHERE AGE>(SELECT AGE FROM S WHERE SN='王华')
B.SELECT SN,AGE,SEX FROM S WHERE SN='王华'
C.SELECT SN,AGE,SEX FROM S
WHERE AGE>(SELECT AGE WHERE SN='王华')
D.SELECT SN,AGE,SEX FROM S WHERE AGE>王华 AGE
A、SELECT SN,AGE,SEX FROM S WHERE AGE>(SELECT AGE FROM S WHERE SN="王华")
B、SELECT SN,AGE,SEX FROM S WHERE SN="王华"
C、SELECT SN,AGE,SEX FROM S WHERE AGE>(SELECT AGE WHERE SN="王华")
D、SELECT SN,AGE,SEX FROM S WHERE AGE > 王华.AGE
A、SELECT S.SN,SC.C#,SC.GRADE FROM S WHERE S.S#=SC.S#
B、SELECT S.SN, SC.C#,SC.GRADE FROM SC WHERE S.S#=SC.GRADE
C、SELECT S.SN,SC.C#,SC.GRADE FROM S, SC WHERE S.S#=SC.S#
D、SELECT S.SN,SC.C#,SC.GRADE FROM S,SC
S(S#,SN,SEX,AGE,DEPT) C(C#,CN) SC(S#,C#,GRADE)其中:S#为学号,SN为姓名,SEX为性别,AGE为年龄,DEPT为系别,C#为课程号, CN为课程名,GRADE为成绩。检索所有比“王华”年龄大的学生姓名、年龄和性别。正确的SELECT语句是______。
A.SELECT SN,AGE,SEX FROM S WHERE AGE>(SELECT AGE FROM S WHERE SN='王华')
B.SELECT SN, AGE, SEX FROM S WHERE SN='王华'
C.SELECT SN,AGE,SEX FROM S WHERE AGE>(SELECT AGE WHERE SN='王华')
D.SELECT SN,AGE,SEX FROM S WHERE AGE>王华AGE
A.SELECT S.SN,SC.C#,SC.GRADE FROM S WHERE S.S#=SC.S#
B.SELECT S.SN, SC.C#,SC.GRADE FROM SC WHERE S.S#=SC.GRADE
C.SELECT S.SN,SC.C#,SC.GRADE FROM S, SC WHERE S.S#=SC.S#
D.SELECT S.SN,SC.C#,SC.GRADE FROM S,SC
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