Types of Indexes in a Database for Optimal Query Performance

Indexes play a crucial role in optimizing query performance in a database. Different types of indexes that are commonly used in a database include:

• Primary Index: A primary index is created on the primary key of a table. It ensures uniqueness and fast retrieval of data.
• Secondary Index: Secondary indexes are created on non-primary key columns to improve the efficiency of data retrieval for specific queries.
• Clustered Index: A clustered index determines the physical order of data in a table and can significantly speed up data retrieval for range queries.
• Non-Clustered Index: Non-clustered indexes store a separate set of pointers to the actual data rows, providing flexibility in query optimization.

Indexes are important for optimal query performance because they help in reducing the number of rows that need to be scanned during query execution, leading to faster data retrieval. They also facilitate quick data retrieval and enable efficient query optimization by the database engine.