I have this table that the rules are: A student is examined in a discipline and obtains a position on the class list. It is known that two students cannot obtain the same position in the same subject. Is this a 3NF database or BCNF, i cant have a 100% sure answer to this
-- Student STUDENT examined in course COURSE
-- obtained position POSITION on class list.
--
test {STUDENT, COURSE, POSITION}
KEY {STUDENT, COURSE}
KEY {COURSE, POSITION}
Nontrivial FDs
:
{STUDENT, COURSE} --> {POSITION}
{COURSE, POSITION} --> {STUDENT}
Use this as a quick check for NF
:
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For each nontrivial |
FD X --> Y |
at least one holds | 2NF 3NF BCNF
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X is a superkey ✔ ✔ ✔
Y is a subkey ✔ ✔
X is not a subkey ✔
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FD X --> Y is trivial iff Y ⊆ X
For both nontrivial FDs X is a superkey; BCNF.