How do different types of indexes differ in database management systems?

In database management systems (DBMS), there are different types of indexes, which differ in structure, performance, and application:

• B-Tree index — the most common type. Suitable for fast searches, sorting, and range queries. Used for equality and comparison operations.

• Hash index — optimal for exact match operations, but does not support range queries. Faster than B-Tree for precise queries, but less versatile.

• Bitmap index — effective for columns with low cardinality (few unique values), such as gender or status. Used in analytical systems.

• Full-text index — designed for fast text searches, supports searching by words and phrases.

• Clustered index — determines the physical order of data storage in a table. In SQL Server, for example, a table can have only one clustered index.

• Non-clustered index — a separate structure that contains keys and pointers to data. Allows creating multiple such indexes on a table.

The choice of index type depends on the nature of queries and data structure. For example, B-Tree is better for range searches, while Hash is suitable for exact key searches.