Indexes

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).

A Primary Index is an automatic, unique index created on a table's primary key for fast data retrieval. It ensures quick lookups, enforces uniqueness, and boosts performance in relational databases.

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 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.

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.