Can you list the main types of indexes used in databases?

Main types of indexes in databases:

• B-Tree index — the most common type, suitable for fast search, sorting, and range queries.
• Hash index — effective for exact key searches, but does not support range queries.
• Bitmap index — used for columns with a small number of unique values, such as gender or status.
• Full-text index — designed for full-text search on text fields.
• Spatial index — used for geographic data and spatial queries.

The choice of index type depends on the nature of the data and the types of queries to the database.