DBMS-Function Dependency and Decomposition Questions and Answers
DBMS Function Dependency and Decomposition questions with answers focus on understanding the relationship between attributes in a relational database. Functional dependency plays a crucial role in normalization, ensuring data consistency and reducing redundancy. Practicing aptitude questions and answers with explanations on this topic helps you strengthen your DBMS fundamentals. These aptitude test practice questions are commonly asked in competitive exams like GATE and placement tests by TCS, Wipro, and Infosys. Learning through solved DBMS questions with solutions PDF enhances your conceptual clarity for both academic and job interviews.
DBMS-Function Dependency and Decomposition
Showing 10 of
39 questions
21. The closure of attribute set X is denoted by:
- X*
- Explanation: X+ represents all attributes functionally determined by X.
- X^
- X°
22. Which of the following is used to find all candidate keys?
- Explanation: Attribute closure helps determine if a set of attributes can function as a key.
- Normalization
- Decomposition
- Join dependency
23. A candidate key is:
- Any super key
- Explanation: A candidate key is a super key with no redundant attributes.
- A primary key only
- A foreign key
24. Which normal form is based purely on functional dependency?
- 1NF
- 2NF
- 3NF
- Explanation: BCNF strictly depends on functional dependencies.
25. A relation is in BCNF if:
- It is in 1NF
- Explanation: BCNF requires all determinants to be candidate keys.
- No partial dependency exists
- No transitive dependency exists
26. Partial dependency violates which normal form?
- 1NF
- Explanation: 2NF eliminates partial dependency on a composite key.
- 3NF
- BCNF
27. Transitive dependency violates which normal form?
- 1NF
- 2NF
- Explanation: 3NF removes transitive dependencies.
- BCNF
28. Which decomposition property ensures no loss of information?
- Dependency preservation
- Explanation: Lossless join guarantees original relation can be reconstructed.
- Minimal cover
- Key preservation
29. A decomposition is lossless if:
- Explanation: A lossless join exists when common attributes act as a key.
- Relations have equal number of tuples
- Dependencies are preserved
- Tables have foreign keys
30. Dependency preservation means:
- No tuples are lost
- Explanation: Dependencies are preserved if they can be checked individually.
- Data redundancy is removed
- Tables are in BCNF