DBMS-Function Dependency and Decomposition Questions and Answers

Practice Mode
Showing 10 of 39 questions
Q21
The closure of attribute set X is denoted by:
  • A X*
  • B Explanation: X+ represents all attributes functionally determined by X.
  • C X^
  • D X°
Answer: Option B
Explanation: X+ represents all attributes functionally determined by X.
Q22
Which of the following is used to find all candidate keys?
  • A Explanation: Attribute closure helps determine if a set of attributes can function as a key.
  • B Normalization
  • C Decomposition
  • D Join dependency
Answer: Option A
Explanation: Attribute closure helps determine if a set of attributes can function as a key.
Q23
A candidate key is:
  • A Any super key
  • B Explanation: A candidate key is a super key with no redundant attributes.
  • C A primary key only
  • D A foreign key
Answer: Option B
Explanation: A candidate key is a super key with no redundant attributes.
Q24
Which normal form is based purely on functional dependency?
  • A 1NF
  • B 2NF
  • C 3NF
  • D Explanation: BCNF strictly depends on functional dependencies.
Answer: Option D
Explanation: BCNF strictly depends on functional dependencies.
Q25
A relation is in BCNF if:
  • A It is in 1NF
  • B Explanation: BCNF requires all determinants to be candidate keys.
  • C No partial dependency exists
  • D No transitive dependency exists
Answer: Option B
Explanation: BCNF requires all determinants to be candidate keys.
Q26
Partial dependency violates which normal form?
  • A 1NF
  • B Explanation: 2NF eliminates partial dependency on a composite key.
  • C 3NF
  • D BCNF
Answer: Option B
Explanation: 2NF eliminates partial dependency on a composite key.
Q27
Transitive dependency violates which normal form?
  • A 1NF
  • B 2NF
  • C Explanation: 3NF removes transitive dependencies.
  • D BCNF
Answer: Option C
Explanation: 3NF removes transitive dependencies.
Q28
Which decomposition property ensures no loss of information?
  • A Dependency preservation
  • B Explanation: Lossless join guarantees original relation can be reconstructed.
  • C Minimal cover
  • D Key preservation
Answer: Option B
Explanation: Lossless join guarantees original relation can be reconstructed.
Q29
A decomposition is lossless if:
  • A Explanation: A lossless join exists when common attributes act as a key.
  • B Relations have equal number of tuples
  • C Dependencies are preserved
  • D Tables have foreign keys
Answer: Option A
Explanation: A lossless join exists when common attributes act as a key.
Q30
Dependency preservation means:
  • A No tuples are lost
  • B Explanation: Dependencies are preserved if they can be checked individually.
  • C Data redundancy is removed
  • D Tables are in BCNF
Answer: Option B
Explanation: Dependencies are preserved if they can be checked individually.

📚 More from Database

← All Topics 🎯 Practice ⏱️ Take Test 🔍 Search
Database
Back to Database
Other Subjects
Questions and Answers for Competitive Exams Various Entrance Test