Indexing & File Organization

Q1. An index in a database is used to:

1. A.Replace primary key usage
2. B.Slow down query results
3. C.Speed up data retrieval✓ Correct
4. D.Increase storage redundancy

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Q2. A primary index is built on:

1. A.An unordered file without sorting
2. B.A foreign key only in the relation
3. C.Any non-key attribute in the table
4. D.The primary key of an ordered file✓ Correct

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Q3. A dense index has:

1. A.An entry for every block in the data file
2. B.Only one entry for the entire data file
3. C.An entry for every record in the data file✓ Correct
4. D.No entries at all in the index structure

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Q4. A sparse index has:

1. A.An entry for every individual record stored
2. B.An entry for each block or group of records✓ Correct
3. C.Entries only for deleted records in the file
4. D.No entries at all in the entire index file

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Q5. A B-tree is a:

1. A.Linear list with sequential access
2. B.Balanced search tree used for indexing✓ Correct
3. C.Binary search tree with two children
4. D.Unbalanced tree without constraints

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Q6. In a B+ tree, all actual data pointers are stored in:

1. A.All nodes equally
2. B.Leaf nodes only✓ Correct
3. C.Root node only
4. D.Internal nodes only

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Q7. Hashing is used for:

1. A.Direct access to records using a hash function✓ Correct
2. B.Sorting data into a specific order on columns
3. C.Sequential access to all records in the file
4. D.Creating views on top of the base table data

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Q8. A secondary index is built on:

1. A.The ordering field of the file
2. B.The primary key field only
3. C.A non-ordering field of a file✓ Correct
4. D.A foreign key field only

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Q9. A clustered index means:

1. A.Data rows are stored randomly without any ordering
2. B.Data rows are physically stored in the index order✓ Correct
3. C.No physical ordering is implied by the index at all
4. D.Multiple indexes exist on the same column of data

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Q10. Which data structure is commonly used for implementing indexes?

1. A.Linked list nodes
2. B.Stack structure
3. C.Queue structure
4. D.B+ tree structure✓ Correct

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Q11. In a B+ tree of order n, an internal node can have at most:

1. A.n+1 keys in the node
2. B.n keys and n children
3. C.n children and n-1 keys✓ Correct
4. D.2n children in total

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Q12. The height of a B+ tree with n records and order p is approximately:

1. A.p*log(n)
2. B.n * p
3. C.log_p(n)✓ Correct
4. D.n / p

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Q13. Static hashing has which disadvantage?

1. A.Fixed number of buckets may lead to overflow as data grows✓ Correct
2. B.It requires B+ trees to function as the base structure
3. C.It is too slow for any practical database use case at all
4. D.It cannot handle any data stored in the database tables

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Q14. Extendible hashing handles growth by:

1. A.Deleting old records to make room for new data entries
2. B.Using a B+ tree instead of hashing for the index data
3. C.Increasing the number of hash functions used for keys
4. D.Doubling the directory and splitting buckets as needed✓ Correct

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Q15. Linear hashing handles growth by:

1. A.Using a fixed number of buckets without any changes
2. B.Splitting all buckets simultaneously at the same time
3. C.Splitting buckets in a linear order, one at a time✓ Correct
4. D.Never splitting any buckets regardless of the load

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Q16. A composite index is an index on:

1. A.A stored procedure reference
2. B.Two or more columns combined✓ Correct
3. C.A view of the base table data
4. D.A single column of the table

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Q17. A covering index is one that:

1. A.Indexes all tables in the database regardless of whether they need indexing
2. B.Has no columns included in it and serves no purpose for query optimization
3. C.Covers only the primary key column and does not include any other attributes
4. D.Contains all columns needed to satisfy a query without accessing the base table✓ Correct

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Q18. A bitmap index is most efficient for:

1. A.Primary key columns that uniquely identify each row
2. B.Columns with unique values that never repeat at all
3. C.Columns with high cardinality (many distinct values)
4. D.Columns with low cardinality (few distinct values)✓ Correct

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Q19. An index-organized table (IOT) stores:

1. A.Data separately from all index structures created
2. B.Data only in memory without disk-based persistence
3. C.Data directly in the index structure (B+ tree)✓ Correct
4. D.Data in flat files without any indexing structures

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Q20. The term fan-out in a B+ tree refers to:

1. A.The number of records stored in the entire data file
2. B.The maximum number of pointers (children) in a node✓ Correct
3. C.The number of leaf nodes at the bottom of the tree
4. D.The total height of the tree from root to leaf level

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Q21. In a B+ tree, the minimum occupancy of internal nodes (non-root) is:

1. A.All pointers must be full
2. B.One pointer (child) as minimum
3. C.Exactly n pointers at all times
4. D.Ceiling of n/2 pointers (children)✓ Correct

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Q22. The global depth in extendible hashing indicates:

1. A.The total number of records stored across all the buckets
2. B.The number of buckets currently allocated in the structure
3. C.The number of bits used to determine the directory entry✓ Correct
4. D.The number of hash functions used for the key computation

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Q23. Local depth in extendible hashing indicates:

1. A.The depth of the B+ tree from the root node to the leaf node level
2. B.The total number of collisions that have occurred in the hash table
3. C.The number of bits used to determine which bucket a record belongs to✓ Correct
4. D.The size of the directory that maps hash values to bucket addresses

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Q24. A hash join in query processing works by:

1. A.Partitioning both relations using the same hash function then joining matching partitions✓ Correct
2. B.Using an index on the join attribute to look up matching tuples from the inner relation
3. C.Sorting both relations on the join attribute first and then merging the sorted result sets
4. D.Using nested loops where each tuple of one relation is compared with every tuple of other

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Q25. R-trees are used to index:

1. A.Text data and documents only
2. B.Temporal data and timestamps
3. C.One-dimensional key values only
4. D.Spatial (multidimensional) data✓ Correct

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Q26. A function-based index is created on:

1. A.A user role that defines access permissions and grants
2. B.A database name used to identify the schema information
3. C.A table name stored in the database system catalog data
4. D.The result of a function applied to one or more columns✓ Correct

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Q27. An inverted index is commonly used in:

1. A.Foreign key enforcement
2. B.Numerical computations only
3. C.Primary key lookups only
4. D.Full-text search engines✓ Correct

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Q28. The order of a B+ tree affects performance because:

1. A.A higher order means more keys per node, reducing tree height and disk I/O✓ Correct
2. B.A higher order always increases the tree height and requires more disk access
3. C.Lower order is always better because smaller nodes fit in memory more easily
4. D.Order has no effect on performance and does not change disk I/O requirements

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Q29. Bulk loading a B+ tree is more efficient than individual insertions because:

1. A.It creates an unbalanced tree that must be rebalanced later
2. B.It sorts data first and builds the tree bottom-up, minimizing splits✓ Correct
3. C.It skips creating the tree entirely and uses a flat file instead
4. D.It uses no sorting and inserts records in their original order

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Q30. A skip list can be used as an alternative to B+ trees for indexing because:

1. A.It provides O(log n) average search, insert, and delete with simpler implementation✓ Correct
2. B.It uses less memory than any other data structure used for indexing purposes
3. C.It is always faster than B+ trees for every type of database query and operation
4. D.It requires no randomization and is fully deterministic in its performance

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