Bitmap Indices

Question 1
Marks : +2 | -2
Pass Ratio : 100%
Which of the following operations is used for the union of bitmaps?
Logical AND
Logical OR
Logical NOT
Logical NOR
Explanation:
The logical OR operation is used for the computation of the union of bitmaps. This is similar to the binary set union operation.
Question 2
Marks : +2 | -2
Pass Ratio : 100%
A _________ on the attribute A of relation r consists of one bitmap for each value that A can take
Bitmap array
Bitmap index
Bitmap excess
Bitmap
Explanation:
A bitmap index on the attribute A of relation r consists of one bitmap for each value that A can take. Each bitmap contains as many bits as the number of records in the relation.
Question 3
Marks : +2 | -2
Pass Ratio : 100%
We create an index in SQL using _______ command
Create index
New index
Create new index
Develop index
Explanation:
We create an index in SQL using the create index command. Eg: create index dept_index on instructor(dept_name).
Question 4
Marks : +2 | -2
Pass Ratio : 100%
What does an existence bitmap do?
It recognizes deleted records
It inserts values into empty bitmaps
It makes sure that no records are deleted
None of the mentioned
Explanation:
An existence bitmap is used to recognize deleted records and not to prevent deletion of records. It also does not insert any records into empty bitmaps.
Question 5
Marks : +2 | -2
Pass Ratio : 100%
State true or false: Bitmaps can be combined with B+ trees
True
False
Explanation:
Bitmaps can be combined with B+ trees for relations where a few attribute values are extremely common.
Question 6
Marks : +2 | -2
Pass Ratio : 100%
We delete and index in SQL using the ________ command
Remove index
Delete index
Drop index
None of the mentioned
Explanation:
We delete and index in SQL using the drop index command. Syntax: drop index ;
Question 7
Marks : +2 | -2
Pass Ratio : 100%
State true or false: Intersection operations are extremely slow on bitmaps
True
False
Explanation:
Intersection operations are extremely fast on bitmaps making them ideal for supporting queries on multiple attributes.
Question 8
Marks : +2 | -2
Pass Ratio : 100%
A bitmap is _______
An array of bits
An index of bits
A function mapping all the bits of data
None of the mentioned
Explanation:
A bitmap is simply an array of bits. A bitmap can be used for various purposes such as bitmap indexing.
Question 9
Marks : +2 | -2
Pass Ratio : 100%
The complement operation in bitmaps is done by using
Logical AND
Logical OR
Logical NOT
Logical NOR
Explanation:
The complement operation in bitmaps is done by using the logical not operator. This is similar to the binary complement operation.
Question 10
Marks : +2 | -2
Pass Ratio : 100%
Intersection of the bitmaps is done by
Logical AND
Logical OR
Logical NOT
Logical NOR
Explanation:
The intersection of the bitmaps is done by the logical AND operation. This is similar to the binary set intersection operation which is done by the logical AND operation.