# Interface: Line

Defined in: [packages/core/src/records/contracts.ts:50](https://github.com/leifriksheim/minca/blob/main/core/src/records/contracts.ts#L50)

A line collection's declaration (spec 09 §6): one line per account, at
`lineKey(root, collection)`. `once` names body fields whose citations
appear at most once along a line. Its keys are closed.

## Properties

| Property | Modifier | Type | Defined in |
| ------ | ------ | ------ | ------ |
| <a id="property-once"></a> `once?` | `readonly` | readonly `string`[] | [packages/core/src/records/contracts.ts:51](https://github.com/leifriksheim/minca/blob/main/core/src/records/contracts.ts#L51) |