Suppose we have the relation schema R(A,B,C,D)with functional dependencies;F{A→B,B→C,C→D,D→A},then R(A,B,C,D)at least is in

A．1NF

B．2NF

C．3NF

D．BCNF

[单选题]Suppose we have the relation schema R(A，B，C，D)with functional dependencies；F{A→B，B→C，C→D，D→A}，then R(A，B，C，D．at least is in (73) ．(73) A．1NFB．2NFC．3NFD．BCNF

[试题]Suppose you have found something wrong with the electronic dictionary that you bought from an online store the other day, Write an email to the customer service center to1) Make a complaint and2) Demand a prompt solutionYou should write about 100words

[单选题]Let R and S be the relation respection respectively：Relation R:A B C Relation S:B C D1 2 3 2 3 46 7 8 2 3 59 7 8 7 8 1The number of tuples that the result of the expression R∞S(Here if natural join of relations R and S) is (69) ．(69) A．1B．4C．7D．10

[单选题]Let R and S be the relation respectively: Relation R: A B C Relation S: B C D 1 2 3 2 3 4 6 7 8 2 3 5 The number of tuplesthat the result of the expression R ∞ S (Here is the natural join of relations R and S) isA．3B．4C．6D．9

[单选题]We don’t have beds in the spacecraft, but we do have sleeping bags. During

[单选题]We don’t have beds in the spacecraft, but we do have sleeping bags. During

[单选题]We don’t have beds in the spacecraft, but we do have sleeping bags. During

[单选题]We don’t have beds in the spacecraft, but we do have sleeping bags. During

[单选题]We don’t have beds in the spacecraft, but we do have sleeping bags. During

[单选题]Some surveys have suggested that the belief that the more money we have, th