Index

Index (definition) Data structure / database object to speed up data retrieval. Stores a sorted copy of one or more columns plus pointers to data rows. Speeds up SELECT queries. Slows down INSERT, UPDATE, DELETE because indexes must be updated. Why indexes help performance Reduce full table scans by quickly locating rows. Make queries with WHERE, JOIN, ORDER BY, GROUP BY faster when they use indexed columns. Types of Indexes [1] Clustered index ...