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
- A1NF
- B2NF
- C3NF
- DBCNF
相关推荐
-
1、We have to point out that the postpone
We have to point out that the postponement of the fulfilment of the contract（）caused us certain expenses.AhadBhaveChasDhaving
-
2、The excavators are（）heavy that we have
The excavators are（）heavy that we have to use a floating crane to life them.AtooBsoCveryDquite
-
3、The food we eat seems to have profou
The food we eat seems to have profound effects on our health.Although science has made enormous steps in making food more fit to eat ,it ha...
-
4、（）we have worked out the loading plan，
（）we have worked out the loading plan，we shall start doing more revision work.AFor nowBEver sinceCNow thatDBy now
-
5、With the world changing fast, we have
With the world changing fast, we have something new______with all by ourselves every day.A deal B dealtC to deal D dealing
-
6、We have received news（）that the wool m
We have received news（）that the wool market on your side is showing signs of recovery.Ato an effectBto this effectCto that effectDto the effect