Could you list different types of indexes used in databases?

Databases use various types of indexes to speed up searches and optimize queries. The main types of indexes:

• B-Tree index — the most common type, suitable for quick searches, sorting, and range queries.
• 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, often in analytical databases.
• Full-text index — designed for fast text searches, for example, in documents or articles.
• Spatial index — for geographic data, supports spatial queries.

Depending on the DBMS and the task, other specialized indexes may also be used. Choosing the right index significantly affects query performance.