Standard (B-tree) and Bitmap

Standard (B-tree) and Bitmap
A standard, B-tree index contains an entry for each value in the index key along with a
disk address of the row where the value is stored. A B-tree index is the default and
most common type of index in an Oracle database.
A bitmap index uses strings of bits to encapsulate values and potential row addresses.
It is more compact than a B-tree index and can perform some types of retrieval more
efficiently. For general use, however, a bitmap index requires more overhead during
row operations on the table and should be used primarily for data warehouse
environments, as described in Oracle Database Data Warehousing Guide.
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