Index (Database)

A database index improves query performance by providing fast access paths to data based on column values.

What is a Database Index?

A database index is a data structure that improves the speed of data retrieval operations by providing efficient access paths to rows based on the values in one or more columns.

Index types

B-tree (default), Hash, Full-text, Spatial, Composite (multi-column).

Common misconceptions

"More indexes are better" — Write performance impact
"Indexes work automatically" — Query must use index
"Primary key is enough" — Query patterns determine needs