Data Warehousing Quiz 3 BITS WILP - Mtec Software Systems

Data Warehousing Quiz 3

BITS WILP - Mtec Software Systems

1. Theoretically, what kind of views we can materialize?
Select one:
a. Any kind of view can be materialized
b. Only involving joins & aggregates
c. Only involving joins
d. Only involving aggregation

Ans: a. Any kind of view can be materialized

2. For partitioning wrt time dimension, which kind of partitioning method is most suitable
Select one:
a. Hash partitioning
b. Composite partitioning
c. Range partitioning
d. List partitioning

Ans: c. Range partitioning

3. User queries and application programs need not be aware of
Select one:
a. Existing partitions only
b. Existing partitions, aggregates, and materialised views
c. Existing aggregates only
d. Existing materialized views only

Ans: b. Existing partitions, aggregates, and materialised views

4. Online aggregation:
Select one:
a. Improves query performance
b. Uses blocking algorithms for evaluating relational operators
c. Does not allow users to prioritise
d. Provides early trends

Ans: d. Provides early trends

5. Size of the bitmap index on a column of a relation R increases with
Select one:
a. An increase in number of attributes of R
b. An increase in column cardinality
c. An increase in the width of the column
d. An increase in number of queries on R

Ans: b. An increase in column cardinality


6. The most generalized term:
Select one:
a. Precomputed joins
b. Precomputed joins with aggregates
c. Precomputed aggregates
d. Materialized views

Ans: c. Precomputed aggregates

7. A query performance enhancing technique that has the least space
overheads:
Select one:
a. View materialization
b. Aggregations
c. Bitmap indices
d. Partitioning

Ans: d. Partitioning

8. Bitmap indexes are:
Select one:
a. Multidimensional indexes
b. Dynamic indexes
c. Multilevel indexes
d. Dense indexes

Ans: a. Multidimensional indexes

9. The aggregate navigation algorithm orders the base and aggregated
fact tables from
Select one:
a. Smallest to the biggest in terms of space requirement
b. Most frequently used to least frequently used
c. Smallest to the biggest in terms of number of tuples
d. 3-way to 2-way to 1-way to base level

Ans: c. Smallest to the biggest in terms of number of tuples

10. Aggregate navigator is a:
Select one:
a. Materialized view generator
b. Middleware
c. End-user tool
d. View maintenance software

Ans: b. Middleware

11. Partitioning wrt time dimension is recommended because:
Select one:
a. It is easier to do as compared to partitioning wrt other dimensions
b. it can be done using range partitioning
c. It facilitates incremental view maintenance
d. It facilitates incremental back up

Ans: c. It facilitates incremental view maintenance
d. It facilitates incremental back up

12. For partitioning wrt product dimension, which kind of partitioning
method is most suitable
Select one:
a. Hash partitioning
b. Composite partitioning
c. Range partitioning
d. List partitioning

Ans: d. List partitioning

13. Which kind of partitioning would create almost equal size partitions:
Select one:
a. Hash partitioning
b. Composite partitioning
c. Range partitioning
d. List partitioning

Ans: a. Hash partitioning

14. Materialized views:
Select one:
a. Store redundant data
b. Always give current data like views
c. Do not need maintenance like views
d. Do not incur space overheads

Ans: a. Store redundant data

15. From the ETL point of view, it is simplest to handle:
Select one:
a. Highly aggregated data
b. Finest granularity data

c. Lightly aggregated data
d. Medium granularity data

Ans: b. Finest granularity data