jiawei wang

• Jul 13th, 2006

 

bitmap indexes are more advantageous than b-tree indexes when the table has millions of rows and the key columns have low cardinality. bitmap indexes provide better performance than b tree indexes when queries often use a combination of multiple where conditions involving the OR operator, the table is read-only, or when there is low update activity on the key columns.

manish.hoiyani

• Sep 14th, 2006

 

b-tree indexes are used for high cardinaties, usuall when we have too many distinct columns.  and bitmap indexex are used for low cardinaties,  usuallywhen we have repeated columns

Adarsh S Pazhayampillil

• Oct 3rd, 2006

 

b-tree indexes are used  usuall when we have too many distinct columns and for high cardinaties .  and bitmap indexex are used for low cardinaties,  usually when we have repeated columns.

Mohammed Abdul Afroze

• Sep 19th, 2007

 

Difference Between B-Tree Index & Bitmap Index.

1. B-tree Index has low cardinality values, where as Bitmap Index has High Cardinality values.
2. B-tree Index is userful for OLTP, where as Bitmap Index is useful for Dataware Housing.
3. B-tree index updates on key values has relatively inexpensive, where as Bitmap index has more expensive.

C.RAMESH

• Oct 17th, 2007

 

Btree Index is very usefull for OLTP and BITMAP index are useful for Decision Support System. When OLTP environment higly level DML activites where doing and it is better to use Btree indexes is better than Bitmap indexes. Where as BITMAP indexes is better for Decision support System because there will be few distinct values.

luttappi

 Profile Answers by luttappi 

• Jun 17th, 2008

 

Other than the way they implemented, one of the functional difference is Bitmap index can index null values where as BTREE index cannot.

subajay

 Profile Answers by subajay 

• Dec 31st, 2008

 

Bitmap index:
------------
A type of index that uses a string of bits to quickly locate rows in a table.  Bitmap indexes are normally used to index low cardinality columns in a  warehouse environment.

Btree index:
------------
A type of index that uses a balanced tree structure for efficient record  retrieval. B-tree indexes store key data in ascending or descending order.

Bidyadhar barik

• Apr 28th, 2012

 

For example – suppose we have using many distinct value for particular column in that time using b-tree index.

Bitmap indexes which is used low cardinaties values .
For example – suppose we have using gender or flag column in that time using bitmap index .

chittu.kotian

 Profile Answers by chittu.kotian 

• May 16th, 2012

 

A B-Tree index stores the index value and the physical rowid of the row. The index values are arranged in the form of leaves. A B-Tree index is used most when the cardinality is high.

A Bitmap index on the other hand is used when the cardinality is low and there are a lot of duplicate data in the indexed column (for example Gender). The Bitmap index consists of 4 columns (first beign the index value, the second and third column consisting of the start and last rowid of the table, and the fourth column consisting of the bitmap. A row having the index value will have its corresponding bit set.

A bit map index generally consumes less space

Vineet

• Oct 12th, 2017

 

1. B-tree Index has high cardinality values, where as Bitmap Index has low Cardinality values.

Prabhat Sahu

• Oct 21st, 2017

 

B-Tree Index:
1. Oracle Default index.
2. Cardinality is High, means less duplicate(more unique records) (i.e. Rowid)
Bitmap Index:
1. Cardinality is Low, means more duplicate.(most of the values are repetative)
2. Flag related columns ( i.e. M/F, Y/N, 1/0 )