【多选题】【消耗次数：1】
设有关系模式R(A，B，C，D)，其数据依赖集：F＝{(A，B)→C，C→D}，那么(A，B)→C是________
①
平凡函数依赖
②
非平凡函数依赖
③
部分函数依赖
④
完全函数依赖
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相关题目
【多选题】
设有关系模式R(A，B，C，D)，其数据依赖集：F＝{(A，B)→C，C→D}，则关系模式R不满足（ ）。
①
A.1NF
②
B.2NF
③
C.3NF
④
D.BCNF
【单选题】
已知关系模式R(A，B，C，D，E)及其上的函数依赖集合F＝{A→D，B→C，E→A}，该关系模式的候选码是（ ）。
①
A.AB
②
B.BE
③
C.CD
④
D.DE
【单选题】
设一个关系为R(A,B,C,D,E),它的最小函数依赖集为FD={A→B,A→C, (C,D) →E},则该关系的候选码为（ ）。
①
(A,C)
②
(C,D)
③
(A,D)
④
(B,D)
【单选题】
设一个关系为R(A,B,C,D,E)，它的最小函数依赖集为FD={A→B,C→D,(A,C)→E}，则该关系的候选码为（ ）。
①
(A,B)
②
(A,C)
③
(A,D)
④
(A,E)
【单选题】
设一个关系为R(A,B,C,D,E),它的最小函数依赖集为FD={A→B,C→D,(A,C) →E},则该关系的候选码为（ ）。
①
(A,B)
②
(A,C)
③
(A,D)
④
(A,E)
【单选题】
设一个关系为R(A,B,C,D,E),它的最小函数依赖集为FD={A→B,B→C, B→D ,D →E},则该关系的候选码为（ ）。
①
(A,B)
②
(A,D)
③
A
④
B
随机题目
【单选题】
It was said that his father _________ .
①
has died
②
died
③
has been dead
④
had died
【单选题】
I haven’t finished my composition . I ________ for two hours and a half.
①
have written it
②
have been writing it
③
wrote it
④
am writing it
【单选题】
I will __________ here till you give me some money.
①
leave
②
not leave
③
come
④
return
【单选题】
“ Has he seen this film ? ” “Yes. He _________ it several days ago.”
①
saw
②
has seen
③
had seen
④
was seeing
【单选题】
A hunter is a man who __________ animals.
①
catch
②
catches
③
will catch
④
was catching
【单选题】
These children are _________ this year than they were last year.
①
moretall
②
moretaller
③
verytaller
④
muchtaller
【单选题】
Yourroomis _______ thanmine.
①
three time big
②
threetimesbig
③
threetimesbigger
④
biggerthreetimes
【单选题】
This book is ________ that one. But __________ than that one.
①
as difficult as ;expensive
②
as more difficult as ; more expensive
③
as difficult as ; more expensive
④
more difficult as ; as expensive
【单选题】
This box is ________ that one.
①
heavy than
②
so heavy than
③
heavier as
④
as heavy as