in Databases retagged by
299 views
0 votes
0 votes

in Databases retagged by
299 views

1 Answer

3 votes
3 votes
Best answer

1 attribute candidate key: None (Every attribute has 2 tuples same)

2 attribute candidate key: (Last Name, Rank), (Last Name, Room Number), (Last Name, Shift), (Rank, Shift), (Room Number, Shift).

(Rank, Room Number) cannot be a 2 attribute candidate key because (Custodian,20) is there twice. So, if we add one more attribute to it, like (Rank, Room Number, Last Name) or (Rank, Room Number, Shift), it becomes a Superkey.

So, only 5 candidate keys.

selected by

2 Comments

edited by
------------
0
0
Please read the solution.

I have considered only minimal superkeys i.e. candidate keys.
0
0

Related questions

0 votes
0 votes
1 answer
1
0 votes
0 votes
1 answer
2
0 votes
0 votes
2 answers
3
1 vote
1 vote
0 answers
4