A database of research articles in a journal uses the following schema. (VOLUME, NUMBER, STARTPAGE, ENDPAGE, TITLE, YEAR, PRICE) The primary key is (VOLUME, NUMBER, STARTPAGE, ENDPAGE) and the following functional dependencies exist in the schema. (VOLUME, NUMBER, STARTPAGE, ENDPAGE) → TITLE (VOLUME, NUMBER) → YEAR (VOLUME, NUMBER, STARTPAGE, ENDPAGE) → PRICE The database is redesigned to use the following schemas. (VOLUME, NUMBER, STARTPAGE, ENDPAGE, TITLE, PRICE) (VOLUME, NUMBER, YEAR) Which is the weakest normal form that the new database satisfies, but the old one does not ?

1NF
2NF
3NF
BCNF

LohaHridoy

4 views

2025-01-04 04:42

1 Answers

AhmedNazir

Option 2 : 2NF

First relational schema:

(VOLUME, NUMBER, STARTPAGE, ENDPAGE, TITLE, YEAR, PRICE)

Primary key: (VOLUME, NUMBER, STARTPAGE, ENDPAGE)

Functional dependencies are:

(VOLUME, NUMBER, STARTPAGE, ENDPAGE) → TITLE

(This dependency is in BCNF, satisfy form X → A, where X is the candidate key)

(VOLUME, NUMBER) → YEAR

(This dependency is not in 2NF, as there is partial dependency in this)

(VOLUME, NUMBER, STARTPAGE, ENDPAGE) → PRICE (BCNF form).

First relational schema is in 1NF.

Second relational schema:

(VOLUME, NUMBER, STARTPAGE, ENDPAGE, TITLE, PRICE) - 1^st

(VOLUME, NUMBER, YEAR) - 2^nd

1^st satisfy

(VOLUME, NUMBER, STARTPAGE, ENDPAGE) → TITLE //BCNF form

(VOLUME, NUMBER, STARTPAGE, ENDPAGE) → PRICE // BCNF form

2^nd satisfy

(VOLUME, NUMBER) → YEAR // According to this, satisfy 2 NF form.

Weakest normal form that new database satisfies but old one doesn’t is 2NF.

4 views Answered 2022-09-04 04:29

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