= Create vector index

Create the custom index with Storage Attached Indexing (SAI):

[source,cql]
----
include::cassandra:example$CQL/vector-search/vector-search-cycling.cql[tag=create-vs-index]
----

For more about SAI, see the xref:../developing/cql/indexing/sai/sai-overview.adoc[Storage Attached Indexing] documentation.

[IMPORTANT]
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The index can be created with options that define the similarity function:

[source]
----
include::cassandra:example$CQL/vector-search/vector-search-cycling.cql[tag=create-vs-index-with-option]
----

Valid values for the `similarity_function` are `DOT_PRODUCT`, `COSINE`, or `EUCLIDEAN`.
====