Can you name different types of index structures used in databases?

Databases use various types of index structures to speed up data search and sorting:

• B-Trees — balanced trees widely used for indexing, providing efficient search, insertion, and deletion.
• B+ Trees — a variant of B-Trees where all values are stored in leaf nodes, simplifying sequential traversal.
• Hash indexes — use hash functions for quick key-based access, effective for exact searches but do not support range queries.
• Bitmap indexes — used for columns with a small number of unique values, employing bitmaps for fast filtering.
• R-trees — used for indexing spatial data (e.g., geographic coordinates).

Each index type is chosen depending on the nature of the data and the types of queries.