设学生关系S(SNO,SNAME,SSEX,SAGE,SDEP)的主码为SNO,学生选课关系SC(SNO,CNO,SCORE)的主码为SNO和CNO,则关系R(SNO,CNO,SSEX,SAGE,SDEP,SCORE)的主码为SNO和CNO,其满足()
A.1NF
B.2NF
C.3NF
D.BCNF
- · 有4位网友选择 B,占比44.44%
- · 有2位网友选择 C,占比22.22%
- · 有2位网友选择 A,占比22.22%
- · 有1位网友选择 D,占比11.11%
A.1NF
B.2NF
C.3NF
D.BCNF
A、
B、
C、
D、
A、delete from CS_student where sno='200215123'
B、update CS_student set sdept='IS' where sno='200215123'
C、insert into CS_student values('200215129','Mike','男',20,'CS')
D、insert into CS_student values('200215128','Tom','男',21,'MA')
A、
B、
C、
D、
A.rs.Find"男",adSeekFirstEQ
B..rs.Seek"男",adSeekFirstEQ
C..rs.Find"男",adSeekLastEQ
D..rs.Seek"男",adSeekLastEQ
A、
B、
C、
D、
A、select sno from sc where grade>90 group by sno having count(cno)>2
B、select sno from sc where grade>90 group by sno having count( distinct sno)>2
C、select sno from sc where grade>90 group by sno having count(*)>2
D、select sno from sc where grade>90 and count(*)>2 group by sno
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