DBMS · Normalization interview questions

39 real DBMS · Normalization questions from the Computer Science Fundamentals bank, as asked in Indian campus drives and tech interviews. Every question has a verified answer and an AI-tutor explanation on placd — free to start.

1. What is Functional dependency?

Junior
  1. A.a form in 2NF where no non-key attribute transitively depends on the primary key
  2. B.a constraint where one attribute set uniquely determines the values of another
  3. C.a dependency where a non-key attribute depends on another non-key attribute
  4. D.a form in BCNF that additionally forbids non-trivial multivalued dependencies
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3. Which statement is correct?

Junior
  1. A.Functional dependency — a dependency where a non-key attribute depends on another non-key attribute
  2. B.Functional dependency — a form in 1NF where every non-key attribute fully depends on the whole candidate key
  3. C.Functional dependency — a constraint where one attribute set uniquely determines the values of another
  4. D.Functional dependency — a form in BCNF that additionally forbids non-trivial multivalued dependencies
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4. What is First normal form?

Junior
  1. A.a stricter 3NF requiring the left side of every non-trivial dependency to be a super key
  2. B.a dependency where a non-key attribute depends on another non-key attribute
  3. C.deliberately adding redundancy to a schema to improve read performance at the cost of duplication
  4. D.a form requiring every attribute to hold only atomic, single-valued, indivisible values
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6. Which statement is correct?

Junior
  1. A.First normal form — a decomposition in which all functional dependencies are still enforceable on individual tables
  2. B.First normal form — the full set of attributes that can be functionally determined from a given set
  3. C.First normal form — a form requiring every attribute to hold only atomic, single-valued, indivisible values
  4. D.First normal form — a constraint where one attribute set uniquely determines the values of another
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7. What is Second normal form?

Mid
  1. A.a stricter 3NF requiring the left side of every non-trivial dependency to be a super key
  2. B.a form in 2NF where no non-key attribute transitively depends on the primary key
  3. C.a form in 1NF where every non-key attribute fully depends on the whole candidate key
  4. D.the full set of attributes that can be functionally determined from a given set
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9. Which statement is correct?

Mid
  1. A.Second normal form — the full set of attributes that can be functionally determined from a given set
  2. B.Second normal form — a dependency where a non-key attribute depends on only part of a composite key
  3. C.Second normal form — a form in 1NF where every non-key attribute fully depends on the whole candidate key
  4. D.Second normal form — a form requiring every attribute to hold only atomic, single-valued, indivisible values
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10. What is Third normal form?

Mid
  1. A.a form in 2NF where no non-key attribute transitively depends on the primary key
  2. B.a sound and complete set of inference rules used to derive all functional dependencies
  3. C.a decomposition that lets the original relation be reconstructed exactly by a natural join
  4. D.a form in 1NF where every non-key attribute fully depends on the whole candidate key
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12. Which statement is correct?

Mid
  1. A.Third normal form — a sound and complete set of inference rules used to derive all functional dependencies
  2. B.Third normal form — a form in 2NF where no non-key attribute transitively depends on the primary key
  3. C.Third normal form — a decomposition in which all functional dependencies are still enforceable on individual tables
  4. D.Third normal form — a form in BCNF that additionally forbids non-trivial multivalued dependencies
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13. What is Boyce-Codd normal form?

Senior
  1. A.a form in BCNF that additionally forbids non-trivial multivalued dependencies
  2. B.the full set of attributes that can be functionally determined from a given set
  3. C.a dependency where a non-key attribute depends on only part of a composite key
  4. D.a stricter 3NF requiring the left side of every non-trivial dependency to be a super key
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15. Which statement is correct?

Senior
  1. A.Boyce-Codd normal form — a form in 1NF where every non-key attribute fully depends on the whole candidate key
  2. B.Boyce-Codd normal form — a stricter 3NF requiring the left side of every non-trivial dependency to be a super key
  3. C.Boyce-Codd normal form — a dependency where a non-key attribute depends on another non-key attribute
  4. D.Boyce-Codd normal form — a form requiring every attribute to hold only atomic, single-valued, indivisible values
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16. What is Fourth normal form?

Senior
  1. A.a dependency where a non-key attribute depends on another non-key attribute
  2. B.a decomposition that lets the original relation be reconstructed exactly by a natural join
  3. C.a form in BCNF that additionally forbids non-trivial multivalued dependencies
  4. D.a decomposition in which all functional dependencies are still enforceable on individual tables
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18. Which statement is correct?

Senior
  1. A.Fourth normal form — a decomposition in which all functional dependencies are still enforceable on individual tables
  2. B.Fourth normal form — a form in 1NF where every non-key attribute fully depends on the whole candidate key
  3. C.Fourth normal form — a decomposition that lets the original relation be reconstructed exactly by a natural join
  4. D.Fourth normal form — a form in BCNF that additionally forbids non-trivial multivalued dependencies
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19. What is Partial dependency?

Mid
  1. A.a decomposition that lets the original relation be reconstructed exactly by a natural join
  2. B.a dependency where a non-key attribute depends on only part of a composite key
  3. C.a dependency where a non-key attribute depends on another non-key attribute
  4. D.a decomposition in which all functional dependencies are still enforceable on individual tables
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21. Which statement is correct?

Mid
  1. A.Partial dependency — a dependency where a non-key attribute depends on another non-key attribute
  2. B.Partial dependency — a decomposition in which all functional dependencies are still enforceable on individual tables
  3. C.Partial dependency — a dependency where a non-key attribute depends on only part of a composite key
  4. D.Partial dependency — a sound and complete set of inference rules used to derive all functional dependencies
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22. What is Transitive dependency?

Mid
  1. A.a dependency where a non-key attribute depends on only part of a composite key
  2. B.a form in BCNF that additionally forbids non-trivial multivalued dependencies
  3. C.a constraint where one attribute set uniquely determines the values of another
  4. D.a dependency where a non-key attribute depends on another non-key attribute
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24. Which statement is correct?

Mid
  1. A.Transitive dependency — a form in BCNF that additionally forbids non-trivial multivalued dependencies
  2. B.Transitive dependency — a form in 2NF where no non-key attribute transitively depends on the primary key
  3. C.Transitive dependency — a form requiring every attribute to hold only atomic, single-valued, indivisible values
  4. D.Transitive dependency — a dependency where a non-key attribute depends on another non-key attribute
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25. What is Lossless join decomposition?

Senior
  1. A.a constraint where one attribute set uniquely determines the values of another
  2. B.a decomposition that lets the original relation be reconstructed exactly by a natural join
  3. C.a form in 1NF where every non-key attribute fully depends on the whole candidate key
  4. D.a dependency where a non-key attribute depends on only part of a composite key
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27. Which statement is correct?

Senior
  1. A.Lossless join decomposition — a stricter 3NF requiring the left side of every non-trivial dependency to be a super key
  2. B.Lossless join decomposition — deliberately adding redundancy to a schema to improve read performance at the cost of duplication
  3. C.Lossless join decomposition — the full set of attributes that can be functionally determined from a given set
  4. D.Lossless join decomposition — a decomposition that lets the original relation be reconstructed exactly by a natural join
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28. What is Dependency preservation?

Senior
  1. A.a decomposition in which all functional dependencies are still enforceable on individual tables
  2. B.a dependency where a non-key attribute depends on another non-key attribute
  3. C.a form in BCNF that additionally forbids non-trivial multivalued dependencies
  4. D.a sound and complete set of inference rules used to derive all functional dependencies
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30. Which statement is correct?

Senior
  1. A.Dependency preservation — a sound and complete set of inference rules used to derive all functional dependencies
  2. B.Dependency preservation — a decomposition in which all functional dependencies are still enforceable on individual tables
  3. C.Dependency preservation — a constraint where one attribute set uniquely determines the values of another
  4. D.Dependency preservation — a form requiring every attribute to hold only atomic, single-valued, indivisible values
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