= Secondary indexes (2i) overview
:description: Secondary indexes (2i).

Secondary indexes (2i) allow you create one or multiple secondary indexes on the same database table, with each 2i based on any column.

*Exception:* There is no need to define an 2i based on a single-column partition key.

xref:developing/cql/indexing/2i/2i-concepts.adoc[Concepts]::
How 2i works and when to use this type of indexing.

// LLP: Should add a quickstart for 2i here.
// xref:getting-started/2i-quickstart.adoc[Quick start]::
// Quickstart for creating and using secondary indexes (2i).

xref:developing/cql/indexing/2i/2i-working-with.adoc[Working with 2i]::
Create, check, alter, drop, and query secondary indexes (2i).

xref:developing/cql/indexing/2i/operations/2i-build.adoc[2i operations]::
Rebuilding and maintaining 2i indexes.

*Reference:* xref:cassandra:reference/cql-commands/create-index.adoc[CREATE INDEX], xref:cassandra:reference/cql-commands/drop-index.adoc[DROP INDEX]