[API reference](https://evolu.dev/docs/api-reference) › [@evolu/common](https://evolu.dev/docs/api-reference/common) › [local‑first/Schema](https://evolu.dev/docs/api-reference/common/local-first/Schema) › SystemColumns

Defined in: [packages/common/src/local-first/Schema.ts:164](https://github.com/evoluhq/evolu/blob/e7144e2bbe9069362b62dec1b64a8aa922b8f1b0/packages/common/src/local-first/Schema.ts#L164)

System columns that are implicitly defined by Evolu.

- `createdAt`: Set by Evolu on row creation, derived from Timestamp.
- `updatedAt`: Set by Evolu on every row change, derived from Timestamp.
- `isDeleted`: Soft delete flag created by Evolu and used by the developer to
  mark rows as deleted.
- `ownerId`: Represents ownership and logically partitions the database.

## Extends

- [`InferType`](https://evolu.dev/docs/api-reference/common/Type/type-aliases/InferType)\<_typeof_ [`SystemColumns`](https://evolu.dev/docs/api-reference/common/local-first/Schema/variables/SystemColumns-1)\>

## Properties

<a id="createdat"></a>

### createdAt

```ts
createdAt: string & Brand<"DateIso">;
```

#### Inherited from

[`SystemColumns`](https://evolu.dev/docs/api-reference/common/local-first/Schema/interfaces/SystemColumns).[`createdAt`](https://evolu.dev/docs/api-reference/common/local-first/Schema/interfaces/SystemColumns#createdat)

---

<a id="isdeleted"></a>

### isDeleted

```ts
isDeleted: 0 | 1 | null;
```

#### Inherited from

[`SystemColumns`](https://evolu.dev/docs/api-reference/common/local-first/Schema/interfaces/SystemColumns).[`isDeleted`](https://evolu.dev/docs/api-reference/common/local-first/Schema/interfaces/SystemColumns#isdeleted)

---

<a id="ownerid"></a>

### ownerId

```ts
ownerId: string & Brand<"Id"> & Brand<"OwnerId">;
```

#### Inherited from

[`SystemColumns`](https://evolu.dev/docs/api-reference/common/local-first/Schema/interfaces/SystemColumns).[`ownerId`](https://evolu.dev/docs/api-reference/common/local-first/Schema/interfaces/SystemColumns#ownerid)

---

<a id="updatedat"></a>

### updatedAt

```ts
updatedAt: string & Brand<"DateIso">;
```

#### Inherited from

[`SystemColumns`](https://evolu.dev/docs/api-reference/common/local-first/Schema/interfaces/SystemColumns).[`updatedAt`](https://evolu.dev/docs/api-reference/common/local-first/Schema/interfaces/SystemColumns#updatedat)