Consider the relation:
BOOK (Book_Name, Author, Edition, Year)
with the data:
a. Based on a common-sense understanding of the above data, what are the possible candidate keys of this relation?
b. Does the above have one or more functional dependency (do not list FDs by applying derivation rules)? If so, what is it? Show how you will remove it by decomposition.
c. Does the resulting relation have an MVD? If so, what is it?
d. What will the final decomposition look like?
a. The only candidate key is {Book_Name, Author, Edition}. From the example, it would appear that {Book_Name, Author, Year} would also be a candidate key but we should consider that some books may have a release cycle which causes multiple editions to appear in a given year.
b. Yes, we have the following FD: Book_Name, Edition ? Year. We can decompose to remove this FD in the following way:
BOOK (Book_Name, Author, Edition)
BOOK_YEAR (Book_Name, Edition, Year)
c. Yes, BOOK contains Book_Name ?? Author and Book_Name ?? Edition.
d. The final decomposition would look like:
BOOK (Book_Name, Edition)
BOOK_AUTHOR (Book_Name, Edition, Author)
BOOK_YEAR (Book_Name, Edition, Year)
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