Index

In the context of databases, an index is a special lookup table that a database search engine can use to speed up data retrieval operations on a database table. Conceptually similar to the index in a textbook, it allows the database management system (DBMS) to quickly locate specific rows based on the values in one or more columns without having to scan the entire table sequentially. This significantly reduces the input/output (I/O) operations required, improving query performance, especially on large datasets.