【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).
A.
1NF
B.
2NF
C.
3NF
D.
BCNFThe construct eobegin Statement1; Statement2; coend means Statement1 and Statement2 are to be executed in parallel. The only two atomic actions in this construct are loading the value of a variable and storing into a variable. For the p
【单选题】For the relation Apply(SSN,cName,state,date,major), suppose college names are unique and students may apply to each college only once, so we have two FDs: cName → state and SSN,cName → date,major. Is ...
【判断题】Suppose we operate a company that produce two kinds of products: shirts and jeans. As we continue to increase production level of shirt, each additional shirt we produced will have fixed opportunity c...