# Untitled string in MDAST Schema

```txt
https://ns.adobe.com/helix/pipeline/mdast#/properties/identifier
```

For associations, an identifier field must be present. It can match an identifier field on another node.

| Abstract            | Extensible | Status         | Identifiable            | Custom Properties | Additional Properties | Access Restrictions | Defined In                                                     |
| :------------------ | :--------- | :------------- | :---------------------- | :---------------- | :-------------------- | :------------------ | :------------------------------------------------------------- |
| Can be instantiated | No         | Unknown status | Unknown identifiability | Forbidden         | Allowed               | none                | [mdast.schema.json*](mdast.schema.json "open original schema") |

## identifier Type

`string`