> For the complete documentation index, see [llms.txt](https://docs.aviowiki.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.aviowiki.com/conventions/aviowiki-ids.md).

# aviowiki IDs

Every object represented in our database, which is individually addressable, is assigned a unique identifier that we call **AID**, or **aviowiki ID**.

![Composition of the AIDs](/files/-MSOVVm9qM9SmZVpOqig)

AIDs are formed of two parts: the namespace (A) and the identifier (B).

The **namespace** is a way to quickly determine what type of object an AID refers to. For example, AIDs starting with `APT` refer to an airport, while those starting with `RWY` refer to a runway. A list of the namespaces used can be found [at the bottom of this page](#undefined).

The **identifier** is a unique combination of eight letters or numbers, all capital (in Regular Expression:`[0-9A-Z]`).

Every namespace, therefore, allows a total amount of 2,821,109,907,456 addressable objects.

To avoid confusion and improve readability we follow these rules when displaying AIDs:

* Always use block capital letters
* Use a font type that makes easy distinctions between similar characters, like the number zero and the letter O
* Separate the namespace portion from the identifier with a dash
* Break down the identifier portion with a dash after 4 characters

### List of namespaces used

| Namespace | Object                                                                         |
| --------- | ------------------------------------------------------------------------------ |
| USR       | [User](/authentication/users.md)                                               |
| APT       | [Airport](/data-models/airport.md)                                             |
| RWY       | [Runway](/data-models/runway.md)                                               |
| ACF       | Aircraft                                                                       |
| PRV       | [Provider](/data-models/provider.md)                                           |
| RGN       | [Region](/data-models/region.md)                                               |
| ONA       | [Airport Operational Note](/data-models/operational-note/operational-notes.md) |
| ONC       | Country Operational Note                                                       |
| ONR       | Region Operational Note                                                        |
| PVP       | Provider Product                                                               |
| FPR       | Fuel Product                                                                   |
| FCO       | Fuel Cost                                                                      |
| FIL       | File Reference                                                                 |
| RAU       | Region Authority                                                               |
| RAC       | Region Authority Contact                                                       |
| AAU       | [Airport Authority](/data-models/authority.md#airport-authority)               |
| AAC       | Airport Authority Contact                                                      |
| CAU       | [Country Authority](/data-models/authority.md#country-authority)               |
| CAC       | Country Authority Contact                                                      |