Indexes

A Clustered Index controls the physical order of data in a table, making range queries and sorting extremely fast. It organizes rows on disk by the index key and is usually the primary key, with only one clustered index allowed per table.

A Composite Index combines two or more columns into a single index to speed up queries filtering or sorting by multiple fields. Column order matters, and the index supports queries starting with the leftmost column(s).

Learn what database indexes are, how they boost query performance, and why they can slow down write operations. Discover how to use indexes wisely to balance speed and efficiency in data retrieval and storage.

A Full-Text Index breaks text data into words (tokens) and indexes them for fast keyword and phrase searches, enabling efficient text search beyond simple exact matches or prefix queries.

A Hash Index uses a hash table internally to provide extremely fast equality lookups (e.g., WHERE key = value), offering average constant-time (O(1)) access by hashing keys to buckets, but it does not support range queries or sorting.