Database-Management-System
August 29, 2024Database-Management-System
August 29, 2024Database-Management-System
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Question 331
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Consider the following relational schemas for a library database : Book (Title, Author, Catalog_no, Publisher, Year, Price) Collection(Title, Author, Catalog_no) with the following functional dependencies :
I. Title, Author → Catalog_no
II. Catalog_no → Title, Author, Publisher, Year
III. Publisher, Title, Year → Price Assume (Author, Title) is the key for both schemas. Which one of the following is true ?
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Both Book and Collection are in BCNF.
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Both Book and Collection are in 3NF.
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Book is in 2NF and Collection in 3NF.
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Both Book and Collection are in 2NF.
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Question 331 Explanation:
Book (Title, Author, Catalog_no, Publisher, Year, Price)
(Author, Title) is the key .
Title, Author → Catalog_no
Catalog_no →Publisher
Here we are having a transitive dependency
(Key→non-key
Non-key→ non-Key)
Hence this relation is not in 3NF.
Collection(Title, Author, Catalog_no)
(Author, Title) is the key
Catalog_no → Title, Author
Since here LHS is not a Key so it is not in BCNF but since the RHS having prime key attribute so it is in 3NF.
(Author, Title) is the key .
Title, Author → Catalog_no
Catalog_no →Publisher
Here we are having a transitive dependency
(Key→non-key
Non-key→ non-Key)
Hence this relation is not in 3NF.
Collection(Title, Author, Catalog_no)
(Author, Title) is the key
Catalog_no → Title, Author
Since here LHS is not a Key so it is not in BCNF but since the RHS having prime key attribute so it is in 3NF.
Correct Answer: C
Question 331 Explanation:
Book (Title, Author, Catalog_no, Publisher, Year, Price)
(Author, Title) is the key .
Title, Author → Catalog_no
Catalog_no →Publisher
Here we are having a transitive dependency
(Key→non-key
Non-key→ non-Key)
Hence this relation is not in 3NF.
Collection(Title, Author, Catalog_no)
(Author, Title) is the key
Catalog_no → Title, Author
Since here LHS is not a Key so it is not in BCNF but since the RHS having prime key attribute so it is in 3NF.
(Author, Title) is the key .
Title, Author → Catalog_no
Catalog_no →Publisher
Here we are having a transitive dependency
(Key→non-key
Non-key→ non-Key)
Hence this relation is not in 3NF.
Collection(Title, Author, Catalog_no)
(Author, Title) is the key
Catalog_no → Title, Author
Since here LHS is not a Key so it is not in BCNF but since the RHS having prime key attribute so it is in 3NF.