[Database Design Normalization: multi-valued dependency] In the relation BOOK(Bo

Question

[Database Design Normalization: multi-valued dependency] In the relation BOOK(Book_Name, Author, Edition, Copyright_Year), there are three multi-valued dependencies (MVDs):

MVD1: {Book_Name} {Author}

MVD2: {Book_Name} {Edition}

MVD3: {Book_Name} {Copyright_Year}

MVD1 is independent of the other two. On the other hand, MVD2 and MVD3 are not independent of each other. Indeed, some books have multiple editions published in the same year and, thus, there is a functional dependency (FD): {Book_Name, Edition} -> {Copyright_Year}.

Now, decompose the relation BOOK into the fourth normal form. In each decomposed relation, underline primary keys, show foreign keys (if there is any), and list the FDs or MVDs applicable to the relation.

Explanation / Answer

fourth normal form

Book_Name -> Author, Edition

Book_Name -> Copyright_Year

Book_Name primary key

Author

Edition

Book_Name primary key

Copyright_Year

Example:

select Book_author.Author, Book_author.Edition, Book_year.Copyright_Year where Book_Name = 'Name of the book';

Functional Dependence

Book_Name -> Author

Book_Name -> Edition

Book_Name -> Author, Edition

Book_Name -> Copyright_Year

Book_Name primary key

Author

Edition

Book_Name primary key

Copyright_Year

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