This is the DBMS questions and answers section on "Normal Forms" with explanation for various interview, competitive examination and entrance test. Solved examples with detailed answer description, explanation are given and it would be easy to understand.
1. In the __________ normal form, a composite attribute is converted to individual attributes.
Answer: Option A
Explanation:
First
The first normal form is used to eliminate the duplicate information.
2. A table on the many side of a one to many or many to many relationship must:
- A. Be in Second Normal Form (2NF)
- B. Be in Third Normal Form (3NF)
- C. Have a single attribute key
- D. Have a composite key
Answer: Option D
Explanation:
Have a composite key
The relation in second normal form is also in first normal form and no partial dependencies on any column in primary key.
3. Tables in second normal form (2NF):
- A. Eliminate all hidden dependencies
- B. Eliminate the possibility of a insertion anomalies
- C. Have a composite key
- D. Have all non key fields depend on the whole primary key
Answer: Option A
Explanation:
Eliminate all hidden dependencies
The relation in second normal form is also in first normal form and no partial dependencies on any column in primary key.
4. Which-one ofthe following statements about normal forms is FALSE?
- A. BCNF is stricter than 3 NF
- B. Lossless, dependency -preserving decomposition into 3 NF is always possible
- C. Loss less, dependency – preserving decomposition into BCNF is always possible
- D. Any relation with two attributes is BCNF
View Answer
Answer: Option C
Explanation:
Loss less, dependency – preserving decomposition into BCNF is always possible
We say that the decomposition is a lossless decomposition if there is no loss of information by replacing r (R) with two relation schemas r1(R1) andr2(R2).
5. Functional Dependencies are the types of constraints that are based on______
- A. Key
- B. Key revisited
- C. Superset key
- D. None of these
Answer: Option A
Explanation:
Key
Key is the basic element needed for the constraints.
