| A)arrived | B)consuming | C)direct | D)exclusively |
| E)including | F)inform | G)raw | H)reached |
| I)relatively | J)remains | K)resources | L)staple |
| M)suggest | N)surprising | O)test |
设数据结构B=(D, R),其中D=( a, b, c, d, e, f )R=( (a, B), (b, C), (c, D), (d, e), (e, f)
[单选题](19)A.) getB.) setC.) trapD.)inform
关系R和S如下图所示,试计算R÷S中有几个元组[1]。 R A B C D a b c d a b e f a b h k b d e f S C D c d
[单选题]给定关系模式R(U,F),U={A,B,C,D,E,F},F={B→F,D→A,A→E, AE→B},那么属性A的闭包为(62),R的候选关键字为(63)。A.ADEB.ABEC.ABCED.ABEF
1.2 Consuming ___ amounts of sugar can lead to serious health problems, includin
Consuming ___ amounts of sugar can lead to serious health problems, including di
[单选题]设有关系模式R(A,B,C,D,E,F),其函数依赖集为F={E→D,C→B,CE→F,B→A}。则R的主键是A.(E,C,B)B.(C,E)C.ED.C
[单选题]关系模式R(U,F),其中U={A,B,C,D,E},F={AC→E,E→D,A→B,B→D}。关系模式R的候选键是(45),(46)是无损连接并保持函数依赖的分解。(56)A.ACB.EDC.ABD.ABC
[单选题]无向图G=(V,E),其中:V={a,b,c,d,e,f},E={(a,b),(a,e),(a,c),(b,c),(c,f),(f,d),(e,d)}
[单选题]无向图G=(V,E),其中:V={a,b,c,d,e,f},E={(a,b),(a,e),(a,c),(b,c),(c,f),(f,d),(e,d)}