# `Uprn`

A Unique Property Reference Number (GeoPlace): up to 12 digits, held as text so no zero is lost: `100023336956`. Personal data.

[People and contact](types.md#people-and-contact); not ordered; personal data (contact); since Jadpo 0.1.0.

## Make one

Build one from its text, `Uprn("1")`, which checks it: text that isn't one breaks `format`.

`text.parse(raw, as: Uprn)` reads one from its text; text that isn't one at all fails `malformed`, such as `0`, `0100023336956` or `1000233369561`.

## Text, JSON and storage

`text.from` writes its canonical text, the one form `text.parse` reads back. JSON sends its canonical text as a string.

| Text | JSON |
|---|---|
| `1` | `"1"` |
| `100023336956` | `"100023336956"` |

It is stored in one column named for the field, of type `text`. `100023336956` is stored as `'100023336956'`.

## Shown to people

`text.format(value, locale:)` shows it to people in their locale.

With `locale: Locale.en_gb`:

| Value | Shown |
|---|---|
| `1` | `1` |
| `100023336956` | `100023336956` |

## Operations

It has the contract's own operations: `text.parse`, `text.from`, `text.format`, `json.read`, `json.write` and `==`. It isn't ordered, so `<` and sorting don't take it. [Every standard type meets one contract](../topics/every-standard-type-meets-one-contract.md) says how they work.