更多"A) produced C) broughtB) obta"的相关试题:
[单项选择]A) produced C) brought
B) obtained D) taken
A. produced
B. obtained
C. brought
D. taken
[单项选择]有关系模式R(S, T, C, D, G),根据语义有如下函数依赖集:F={(S, C)→T,C→D,(S, C)→G, T→C}。关系模式R的候选码( )。
A. 只有1个,为(S, C)
B. 只有1个,为(S, T)
C. 有2个,为(S, C)和(S, T)
D. 有2个,为(S, C)和(T)
[单项选择]A) reduced C) descended
t5) revised D) delayed
[单项选择]关系模式R(C,T,H,R,S),有如下函数依赖集: F={C→T,(H,R)→C,(H,T)→R,(H,S)→R} 关系模式R的码是______。
A. C
B. (H,
C. (H,
D. (H,
[单项选择]有关系模式A(C,T,H,R,S),根据语义有如下函数依赖集:F=C→T,(H,R)→C,(H,T)→R,(H,S)→R,则关系模式A的码是( )。
A. C
B. (H,T)
C. (H,R)
D. (H,S)
[单项选择]关系模式R(C,T,H,R,S),有如下函数依赖集: F={C→T,(H,R)→C,(H,T)→R,(H,S)→R} 关系模式R的码是______。
A. C
B. (H,
C. (H,
D. (H,
[单项选择]有关系R(A,B,C,D) 和关系S(A,B,C,D,E,F),关系T是R与S的笛卡尔积,即:T=R×S。则关系T的属性个数是( )。
A. 4
B. 6
C. 10
D. 24
[单项选择]有关系R(A,B,C,D)和关系S(A,B,C,D,E,F),关系T是R与S的笛卡儿积,即T=R×S。则关系T的属性个数是( )。
[单项选择]A) As knowing C) Known
B) Well knowing D) To know well
A. As knowing
B. Well knowing
C. Known
D. To know well
[单项选择]The data accumulated was obtained through
[单项选择]A) a only C) the only
B) a unique D) the unique
A. a only
B. a unique
C. the only
D. the unique
[单项选择]A) to be C) to come
B) to go D) to reach
A. to be
B. to go
C. to come
D. to reach