What types of indexes exist in databases?

Databases have different types of indexes that help speed up data search and sorting:

• B-Tree index — the most common type, suitable for quick range searches and exact matches.
• Hash index — effective for exact key lookups but does not support range queries.
• Bitmap index — used for columns with a small number of unique values, well-suited for analytical queries.
• Full-text index — designed for fast text searches, supports word and phrase searches.
• Spatial index — used for geographic data, such as R-Tree.

The choice of index depends on the data type and the nature of the queries. For example, B-Tree indexes are created for columns frequently used in WHERE conditions, and full-text indexes are used for text searches.