Question
Which of the following correctly describes the second
normal form (2NF) in database normalization?Solution
A table is in Second Normal Form (2NF) if it is in First Normal Form (1NF) and all non-key attributes are fully functionally dependent on the entire primary key, not just part of it. This eliminates partial dependencies, which occur when a non-key attribute depends on only a part of a composite primary key. Why Other Options Are Incorrect:
- The table contains no duplicate rows: This is a general requirement for any relational database, not specific to 2NF.
- Every determinant is a candidate key: This describes Boyce-Codd Normal Form (BCNF) , a stricter form of 3NF.
- The table is free from transitive dependency: This is achieved in Third Normal Form (3NF) , not 2NF.
- All attributes depend on the primary key: This defines 1NF but does not address partial dependencies, a key focus of 2NF.
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