---
title: "MappingIdentifier"
description: "an id that becomes an identifier"
section: concepts
address: /concepts/mappingidentifier
contract: 0476e35e6e275db5
---

# MappingIdentifier

an id that becomes an identifier

[figure: MappingIdentifier is a value at none scope. The drawing shows its fields and the objects that they point at.]

| property | value |
|---|---|
| kind | value |
| scope | none |
| key | none |
| store | none |
| family | sources |



## Fields


| field | type | required | note |
|---|---|---|---|
| `id` | `text` | yes |  |
| `namespace` | `text` | yes |  |
| `trust_rank` | `count` | yes |  |
| `prefix` | `text` | no | put before the value, for a platform-and-handle key |
| `prefix_by_kind` | `{text:text}` | no | for an object whose kind field decides the prefix (a table of comments and submissions together), the prefix for each kind word; the row's kind word chooses it, and a word absent here leaves the row without an own id |



## Routes that use it
No route takes or returns MappingIdentifier directly. The record holds it, and the objects that point at it reach it.