Difference between bitmap and btree index in oracle

Structural difference between bitmap and btree index in oracle.

Structural difference between bitmap and btree index

Btree
It is made of branch nodes and leaf nodes. Branch nodes holds prefix key value along with the link to the leaf node. The leaf node in turn contains the indexed value and rowed.

Bitmap
It simply consists of bits for every single distinct value. It uses a string of bits to quickly locate rows in a table. Used to index low cardinality columns.