Database Index and Query Performance

A database index is a data structure that improves the speed of data retrieval operations on a database table. It works by creating an ordered list of pointers to the actual data rows, which allows the database system to quickly locate specific rows based on the indexed columns.

By using a database index, query performance is significantly improved as the database engine can quickly narrow down the search space and directly access the required data without having to scan the entire table. This speeds up query execution time, especially for large tables and complex queries.

In summary, a database index helps improve query performance by reducing the time it takes to retrieve data from the database table, resulting in faster and more efficient query processing.