Bitmap indexes in DBMS Theory - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the sentence to describe bitmap indexes.

DBMS Theory

Bitmap indexes are most efficient when the column has [1] cardinality.

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Alow

Bhigh

Cunique

Drandom

Attempts:

3 left

💡 Hint

Common Mistakes

Confusing low cardinality with high cardinality.

Thinking bitmap indexes are best for unique values.

Bitmap indexes work best on columns with low cardinality, meaning few distinct values, because they use bitmaps to represent each value efficiently.

2fill in blank

medium

Complete the sentence to explain a benefit of bitmap indexes.

DBMS Theory

Bitmap indexes improve query performance by allowing [1] operations on bitmaps.

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Aarithmetic

Blogical

Csorting

Daggregation

Attempts:

3 left

💡 Hint

Common Mistakes

Assuming bitmap indexes perform arithmetic operations.

Confusing sorting with logical operations.

Bitmap indexes allow logical operations like AND, OR, and NOT on bitmaps, which speeds up complex queries.

3fill in blank

hard

Fix the error in the statement about bitmap indexes.

DBMS Theory

Bitmap indexes are ideal for columns with [1] unique values.

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Afew

Bmany

Cno

Drandom

Attempts:

3 left

💡 Hint

Common Mistakes

Choosing 'many' unique values which is incorrect.

Misunderstanding the term 'unique values' in this context.

Bitmap indexes are ideal for columns with few unique values, which means low cardinality.

4fill in blank

hard

Fill both blanks to complete the explanation of bitmap index usage.

DBMS Theory

Bitmap indexes use [1] to represent each distinct value and are efficient for [2] queries.

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Abitmaps

Bhashes

Clow-cardinality

Dhigh-cardinality

Attempts:

3 left

💡 Hint

Common Mistakes

Confusing bitmaps with hashes.

Choosing high-cardinality which is less efficient for bitmap indexes.

Bitmap indexes use bitmaps to represent each distinct value and are efficient for low-cardinality queries.

5fill in blank

hard

Fill all three blanks to complete the bitmap index creation example.

DBMS Theory

CREATE BITMAP INDEX [1] ON [2]([3]);

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Aidx_gender

Bemployees

Cgender

Dsalary

Attempts:

3 left

💡 Hint

Common Mistakes

Using a column name as the index name incorrectly.

Mixing up table and column names.

This command creates a bitmap index named idx_gender on the gender column of the employees table.