Database Design & Normalization

Q1. Normalization in databases is the process of:

1. A.Adding redundant data to speed up query processing
2. B.Deleting all data from every table in the database
3. C.Creating as many tables as possible in the schema
4. D.Organizing data to reduce redundancy and dependency✓ Correct

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Q2. First Normal Form (1NF) requires:

1. A.All attributes are restricted to numeric
2. B.No foreign keys exist within the tables
3. C.All attributes contain atomic values only✓ Correct
4. D.Tables have only one column of any data

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Q3. A functional dependency X → Y means:

1. A.The value of Y uniquely determines the value of X
2. B.X and Y always contain the same identical values
3. C.X and Y are completely unrelated to each other
4. D.The value of X uniquely determines the value of Y✓ Correct

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Q4. Redundancy in a database leads to:

1. A.Insertion, deletion, and update anomalies✓ Correct
2. B.Better data integrity and consistency
3. C.Faster queries and improved performance
4. D.Simplified database design structure

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Q5. An update anomaly occurs when:

1. A.A table is created for the first time in the schema
2. B.A new row is inserted into an existing data table
3. C.The same data must be changed in multiple places✓ Correct
4. D.An index is dropped from a column in the database

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Q6. Second Normal Form (2NF) requires:

1. A.Only atomic values without any other constraints
2. B.1NF and no partial dependency on the primary key✓ Correct
3. C.No functional dependencies of any kind at all
4. D.All attributes must serve as keys in the table

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Q7. Third Normal Form (3NF) requires:

1. A.No attributes defined at all in it
2. B.Only 1NF without other constraints
3. C.2NF and no transitive dependencies✓ Correct
4. D.All attributes are primary key parts

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Q8. A transitive dependency exists when:

1. A.Two keys depend on each other in a circular dependency
2. B.A key attribute depends on a non-key attribute directly
3. C.A non-key attribute depends on another non-key attribute✓ Correct
4. D.No dependencies exist between any attributes at all

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Q9. A partial dependency exists when:

1. A.A non-key attribute depends on the entire composite primary key
2. B.A non-key attribute depends on part of a composite primary key✓ Correct
3. C.No dependencies exist between any attributes in the data table
4. D.All attributes depend on all keys defined in the relation schema

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Q10. Denormalization is:

1. A.Removing all tables and their data from the entire database
2. B.Intentionally introducing redundancy to improve read performance✓ Correct
3. C.Deleting all indexes to reduce overall storage requirements
4. D.Normalizing the schema to a higher normal form than before

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Q11. Boyce-Codd Normal Form (BCNF) is stricter than 3NF because:

1. A.Every determinant must be a candidate key✓ Correct
2. B.It allows partial dependencies on some keys
3. C.It requires no functional dependencies at all
4. D.It requires only atomic values in each field

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Q12. A relation in BCNF is always in:

1. A.4NF
2. B.1NF
3. C.5NF
4. D.3NF✓ Correct

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Q13. A multivalued dependency X →→ Y exists when:

1. A.Y is a primary key attribute that uniquely identifies every tuple
2. B.A set of values of Y is determined by X, independent of other attributes✓ Correct
3. C.X functionally determines Y through a standard functional dependency
4. D.No dependency exists between the attributes X and Y in the relation

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Q14. Fourth Normal Form (4NF) requires:

1. A.No functional dependencies of any kind in the schema
2. B.BCNF and no non-trivial multivalued dependencies✓ Correct
3. C.All attributes serve as keys in the relation structure
4. D.Only 1NF without any additional constraints applied

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Q15. A lossless join decomposition ensures that:

1. A.Some data is always permanently lost during the decomposition process
2. B.Joining the decomposed relations reproduces the original relation exactly✓ Correct
3. C.Extra spurious tuples are generated when joining decomposed relations
4. D.Only key attributes are preserved in the decomposed relation fragments

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Q16. Which normal form deals with join dependencies?

1. A.Third Normal Form (3NF)
2. B.First Normal Form (1NF)
3. C.Second Normal Form (2NF)
4. D.Fifth Normal Form (5NF)✓ Correct

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Q17. Armstrong's axiom of reflexivity states:

1. A.If X determines Y, then XZ determines YZ for any Z
2. B.If Y is a subset of X, then X determines Y✓ Correct
3. C.If X determines Y and Y determines Z, then X determines Z
4. D.If X determines Y, then Y also determines X always

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Q18. Armstrong's axiom of augmentation states:

1. A.If X determines Y and Y determines Z, then X determines Z
2. B.If X determines Y, then Y also determines X in reverse
3. C.If X determines Y, then XZ determines YZ for any attribute Z✓ Correct
4. D.If Y is a subset of X, then X functionally determines Y

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Q19. The canonical (minimal) cover of a set of FDs:

1. A.Is always empty regardless of the original dependency set
2. B.Contains all possible FDs derivable from the original set
3. C.Has maximum redundancy among all its functional dependencies
4. D.Has no redundant dependencies and no extraneous attributes✓ Correct

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Q20. A dependency-preserving decomposition ensures that:

1. A.All original functional dependencies can be enforced without joining decomposed tables✓ Correct
2. B.All tables in the decomposition must have exactly the same schema and attributes
3. C.Joins are never needed between any of the resulting decomposed relation fragments
4. D.Some functional dependencies are always lost during the process of decomposition

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Q21. Fifth Normal Form (5NF) eliminates:

1. A.Join dependencies that are not implied by candidate keys✓ Correct
2. B.Multivalued dependencies among the stored data attributes
3. C.Functional dependencies between attributes in the table
4. D.All types of dependencies regardless of their categories

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Q22. A relation is in Domain-Key Normal Form (DKNF) if:

1. A.Every constraint is a logical consequence of domain constraints and key constraints✓ Correct
2. B.It satisfies only the requirements of first normal form and nothing beyond that
3. C.All attributes in the relation must serve as keys for unique identification
4. D.It has no constraints of any type defined on its attributes or relationships

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Q23. The synthesis algorithm for 3NF decomposition:

1. A.Always produces a BCNF decomposition that preserves all functional dependencies
2. B.Uses the canonical cover to create a dependency-preserving, lossless decomposition✓ Correct
3. C.Only works for binary relations with exactly two attributes in the schema
4. D.Removes all dependencies from the relation during the decomposition procedure

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Q24. It is possible to have a decomposition that is lossless but NOT dependency-preserving in:

1. A.BCNF decomposition✓ Correct
2. B.1NF decomposition
3. C.Any decomposition
4. D.No decomposition

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Q25. The chase algorithm is used to:

1. A.Create indexes on frequently queried columns
2. B.Optimize storage allocation across disk pages
3. C.Test whether a decomposition is lossless✓ Correct
4. D.Test whether a query is syntactically correct

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Q26. A trivial functional dependency is one where:

1. A.The right side is a subset of the left side✓ Correct
2. B.The left side is empty with no attributes
3. C.No attributes are involved in the FD
4. D.Both sides are identical key attributes

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Q27. An extraneous attribute in an FD X → Y is an attribute that:

1. A.Can be removed from X or Y without changing the closure✓ Correct
2. B.Cannot be removed under any circumstance from the FD
3. C.Must always be present in the functional dependency rule
4. D.Is a primary key attribute that cannot ever be removed

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Q28. Normalization theory is based on which mathematical concept?

1. A.Functional dependencies and their properties✓ Correct
2. B.Probability theory and statistical methods
3. C.Set theory only without other foundations
4. D.Graph theory only without other foundations

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Q29. When BCNF decomposition is not dependency-preserving, the alternative is:

1. A.Go to 4NF which eliminates all multivalued dependencies from the relation
2. B.Accept 3NF which guarantees both lossless join and dependency preservation✓ Correct
3. C.Denormalize completely to avoid any decomposition of the original table
4. D.Use 1NF only which requires just atomic values in every attribute field

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Q30. A fully functionally dependent attribute means:

1. A.Removing any attribute from the left side of the FD destroys the dependency✓ Correct
2. B.The attribute has no dependencies of any kind on other attributes at all
3. C.The attribute is part of the key and contributes to unique identification
4. D.The attribute depends on a single column only in the current relation schema

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