Slideshow:
How to use a bitmap index - Example
Input data:
Bitmap indexes on multiple fields is a
multi-dimensional index !
Answering
partial match queries
using bitmap indexes
Input data:
Answering
range queries
using bitmap indexes
Input data:
Answering
range queries
using bitmap indexes
Input data:
Answering
range queries
using bitmap indexes
Input data:
- Example query:
- Find people
(who by jewelry) such that:
age = 50 salary = 100
Answer:
123456789012 =========================== Bitmap index for age = 50 = 001110000010 Bitmap index for salary = 100 = 000100000000 ----------------------- AND: 000100000000 Record #4 !!! - Find people
(who by jewelry) such that:
- Fact:
- When you have bitmap indexes on
different fields
(of a record),
the bitmap indexes are
multi-dimensional
- There are some multi-dimensional queries that can be answered efficiently using bitmap indexes
- When you have bitmap indexes on
different fields
(of a record),
the bitmap indexes are
multi-dimensional
- Query:
- Find people (buyers of jewelry) whose age = 50
Solution:
Bitmap index for age: Value 123456789012 ------------------------------ 25 100000001000 30 000000010000 45 010000000100 50 001110000010 <----- These people !!! 60 000000000001 70 000001000000 85 000000100000 Records: 3, 4, 5 and 11
- Query:
- Find people (buyers of jewelry) where:
45 ≤ age ≤ 55 100 ≤ salary ≤ 200
Solution:
Bitmap index for age: Value 123456789012 ------------------------------ 25 100000001000 30 000000010000 45 010000000100 45 ≤ age ≤ 50 50 001110000010 60 000000000001 70 000001000000 85 000000100000 Or value = 011110000110
Bitmap index for salary: Value 123456789012 ------------------------------- 60 110000000000 75 001000000000 100 000100000000 110 000001000000 100 ≤ salary ≤ 200 120 000010000000 140 000000100000 260 000000010001 275 000000000010 350 000000000100 400 000000001000 Or value = 000111100000
(45 ≤ age ≤ 50) AND (100 ≤ salary ≤ 200): 123456789012 ======================= 011110000110 000111100000 (AND) --------------- 000110000000 Records: 4 and 5 - Find people (buyers of jewelry) where: