## Syntax
```mermaid
%%{init: {
'theme': 'base',
'flowchart': { 'padding': '7', 'nodeSpacing': '20', 'rankSpacing': '20' },
'themeVariables': {
'fontSize': '11px',
'fontFamily': 'Arial'
}
}}%%
flowchart LR
Start((START)) --> UUID_NS_X500[UUID_NS_X500]:::quoted
UUID_NS_X500 --> End((END))
```
## Purpose
The `UUID_NS_X500` SQL function returns the namespace of X.500 distinguished names, a constant of RFC 9562, as the first argument of [[UUID_GENERATE_V3]] and [[UUID_GENERATE_V5]]. The function has the name of the function of the `uuid-ossp` extension of PostgreSQL.
Available from release 28.0.
See also [[UUID_NS_DNS]], [[UUID_NS_URL]], [[UUID_NS_OID]] and [[UUID_NS_X500]].
Returns: the namespace, of data type `guid`.
## Examples
The following example returns the namespace:
```sql
select uuid_ns_x500()
------------------------------------
6ba7b814-9dad-11d1-80b4-00c04fd430c8
```