# How to activate unaccent search

**URL:** https://discuss.tryton.org/t/how-to-activate-unaccent-search/5586
**Category:** System Administrator
**Created:** [October 7, 2022, 5:30pm UTC](https://discuss.tryton.org/t/how-to-activate-unaccent-search/5586 "2022-10-07T17:30:41Z")
**Posts on this page:** 1
**Page:** 1

<div class="post-metadata">

### Author: ![ced](https://discuss-cdn.tryton.org/user_avatar/discuss.tryton.org/ced/32/1237_2.png) [@ced](https://discuss.tryton.org/u/ced)
#### Post date: [October 7, 2022, 5:30pm UTC](https://discuss.tryton.org/t/how-to-activate-unaccent-search/5586/1 "2022-10-07T17:30:41Z")

</div>

## Introduction

By default Tryton tries to search for most of the `Char` fields if the database supports it.

## Activate on PostgreSQL

The unaccent search is done in PostgreSQL thanks to the [unaccent extension](https://www.postgresql.org/docs/current/unaccent.html).  
You can activate it with:

```sql
CREATE EXTENSION unaccent;

```

The `unaccent` function cannot be used as an expression in an index because it is not immutable. This is mainly because it depends on a dictionary file on the server.

However it is possible to modify the function with:

```sql
ALTER FUNCTION unaccent(text) IMMUTABLE;
ALTER FUNCTION unaccent(regdictionary, text) IMMUTABLE;

```

or by creating a new function:

```sql
CREATE OR REPLACE FUNCTION f_unaccent(regdictionary, text)
  RETURNS text
  LANGUAGE c IMMUTABLE PARALLEL SAFE STRICT AS
'$libdir/unaccent', 'unaccent_dict';

CREATE OR REPLACE FUNCTION f_unaccent(text)
  RETURNS text
  LANGUAGE sql IMMUTABLE PARALLEL SAFE STRICT AS
$func$
SELECT f_unaccent('unaccent', $1)
$func$;

```

or if you do not have the privileges required for C extensions:

for PostgreSQL \>= 14

```sql
CREATE OR REPLACE FUNCTION immutable_unaccent(value text)
  RETURNS text
  LANGUAGE sql IMMUTABLE PARALLEL SAFE STRICT 
RETURN (SELECT unaccent('unaccent', value));

CREATE OR REPLACE FUNCTION immutable_unaccent(dict regdictionary, value text)
  RETURNS text
  LANGUAGE sql IMMUTABLE PARALLEL SAFE STRICT
RETURN (SELECT unaccent(dict, value));

```

for PostgreSQL \< 14

```sql
CREATE OR REPLACE FUNCTION immutable_unaccent(text)
  RETURNS text
  LANGUAGE sql IMMUTABLE PARALLEL SAFE STRICT AS
$func$
SELECT unaccent('unaccent', $1)
$func$;

CREATE OR REPLACE FUNCTION immutable_unaccent(regdictionary, text)
  RETURNS text
  LANGUAGE sql IMMUTABLE PARALLEL SAFE STRICT AS
$func$
SELECT unaccent($1, $2)
$func$;

```