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Hi there I'm still learning for my examination and I got this exercise:

A table is given:

F-Name,           F-Nation,    Team-Name,   Team-Nation 
-------------------------------------------------------
Lance Armstrong,     USA,   Discovery Channel,   USA 
Jose Luis Rubiera,   ESP,   Discovery Channel,   USA 
Jan Ullrich,         GER,   Team Telekom,        GER 
Andreas Klöden,      GER,   Team Telekom,        GER 
Davide Rebellin,     IT,    Team Gerolsteiner,   GER 

a) Which are the candidate keys?

b) Which non-trivial functional dependencies existing?

c) Is the table in 2NF (second normal form)? If not modify the table to be in 2NF.

d) Is the table in 3NF (third normal form)? If not modify the table to be in 3NF.


a) I would say that the candidate keys are (F-Name, Team-Name) or (F-Name, Team-Nation)

b) The dependencies are:

Team-Name -> Team-Nation
F-Name -> F-Nation

c) no it is not in 2NF because Team-Nation is not dependant from the F-Name which is part of the key candidate.

Table after normalization to 2NF:

Table driver

F-Name, F-Nation, Team-Name

Table teams

Team-Name, Team-Nation

d) I couldn't find any transitive relations so I guess the solution of c) would be in 3NF also am I right?

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closed as unclear what you're asking by jcolebrand Jul 9 at 18:40

Please clarify your specific problem or add additional details to highlight exactly what you need. As it's currently written, it’s hard to tell exactly what you're asking. See the How to Ask page for help clarifying this question.If this question can be reworded to fit the rules in the help center, please edit the question.

    
Based on the data, F-Name seems to be a candidate key by itself. And since the candidate keys can be deduced by dependies, you have missed some dependencies. –  ypercube Feb 2 at 22:35
    
b) If the dependencies were only those two, the only candidate key would be (F-Name, Team-Name). How did you come with the second one? –  ypercube Feb 2 at 22:39

1 Answer 1

Ok so I can say on a) there are two solutions. If F-Name is Unique the candidate key is F-Name otherwise F-Name, Team-Name

b) The dependencies are:

F-Name -> F-Nation, Team-Name
Team-Name -> Team-Nation

and my solutions on c) and d) are right?

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1  
Please use the edit link on your question to add additional information. The Post Answer button should be used only for complete answers to the question. –  Colin 't Hart Jul 9 at 19:22

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