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
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39 questions
11. Decomposition helps in eliminating some of the problems of bad design such as
- redundancy
- inconsistencies
- anomalies
- all of these
12. The word loss in lossless refers to the
- loss of information.
- loss of attributes
- loss of relations
- none of these.
13. The dependency preservation decomposition is a property of decomposed relational database schema D in which each functional dependency D----->Y specified in F
- appeared directly in one of the relation schemas R1 in the deomposed D.
- could be inferred from dependencies that appear in some Ri.
- both (a) and (b)
- none of these.
14. The set of attributes X will be fully functionally dependent on the set of attributes Y if the following conditions are satisfied:
- X is functionally dependent on Y.
- X is not functionally dependent on any subset of Y.
- both (a) and (b)
- none of these
15. Which of the following best defines a functional dependency in DBMS?
- A relationship between two tables
- Explanation: A functional dependency specifies a constraint where one set of attributes uniquely determines another set.
- A rule that defines primary keys only
- A dependency between tuples
16. If A → B holds, it means:
- B determines A
- A and B are independent
- Explanation: A → B means the value of A determines the value of B.
- A and B must be primary keys
17. Which of the following is a trivial functional dependency?
- A → B
- AB → C
- Explanation: A functional dependency is trivial if the right-hand side is a subset of the left-hand side.
- B → A
18. Which rule states that if A → B then A → BC also holds?
- Transitivity
- Reflexivity
- Explanation: Augmentation allows adding attributes to both sides of a dependency.
- Decomposition
19. Which of the following is NOT an Armstrong’s axiom?
- Reflexivity
- Transitivity
- Explanation: Union is a derived rule, not a basic Armstrong axiom.
- Augmentation
20. If A → B and B → C, then A → C is derived using:
- Augmentation
- Reflexivity
- Explanation: Transitivity allows inference of indirect dependencies.
- Decomposition