An index is a database object used to improve query performance.
It helps SQL find data faster without scanning the entire table.
Indexes are similar to book indexes.
Without an index, SQL checks every row one by one.
This process becomes slow when tables grow large.
Indexes reduce search time significantly.
Indexes are usually created on columns that are frequently searched.
Common examples include id, email, or username columns.
An index stores column values in a sorted structure.
This allows SQL to locate records quickly.
Indexes improve SELECT query speed.
Indexes increase read performance but slightly slow down insert and update operations.
Proper index usage is important for balanced performance.