## Add items to an existing dataset

**post** `/v5/dataset-items/batch`

Add one or more items in a single batch to a dataset that already exists.

Use this to append items to an existing dataset; to create a dataset together with its initial
items in one call, use POST /v5/datasets instead (this endpoint does not create datasets).
Items are only ever added in a batch — there is no single-item create endpoint. The target
dataset is identified by the required dataset_id in the request body, and each entry in data
(at least one is required) becomes one item, optionally paired with the files entry at the same
list index — when files is supplied it must be the same length as data. Each referenced file
must exist and be a supported media format, and item keys may not collide with reserved dataset-
or evaluation-item field names. The target dataset must not be archived. The batch is applied as
a new dataset version snapshot rather than mutating existing versions, and the created items are
returned.

### Body Parameters

- `data: array of map[unknown]`

  Items to be added to the dataset

- `dataset_id: string`

  Identifier of the target dataset

- `files: optional array of map[string]`

  Files to be associated to the dataset

### Returns

- `items: array of DatasetItem`

  - `id: string`

    The unique identifier of the entity.

  - `content_hash: string`

  - `created_at: string`

    The date and time when the entity was created in ISO format.

  - `created_by: Identity`

    The identity that created the entity.

    - `id: string`

    - `type: "user" or "service_account"`

      - `"user"`

      - `"service_account"`

    - `object: optional "identity"`

      - `"identity"`

  - `data: map[unknown]`

  - `updated_at: string`

    The date and time when the entity was last updated in ISO format.

  - `archived_at: optional string`

    The date and time when the entity was archived in ISO format.

  - `dataset_id: optional string`

  - `files: optional map[string]`

  - `object: optional "dataset.item"`

    - `"dataset.item"`

- `object: optional "list"`

  - `"list"`

### Example

```http
curl https://api.egp.scale.com/v5/dataset-items/batch \
    -H 'Content-Type: application/json' \
    -H "x-api-key: $SGP_API_KEY" \
    -d '{
          "data": [
            {
              "foo": "bar"
            }
          ],
          "dataset_id": "dataset_id"
        }'
```

#### Response

```json
{
  "items": [
    {
      "id": "id",
      "content_hash": "content_hash",
      "created_at": "2019-12-27T18:11:19.117Z",
      "created_by": {
        "id": "id",
        "type": "user",
        "object": "identity"
      },
      "data": {
        "foo": "bar"
      },
      "updated_at": "2019-12-27T18:11:19.117Z",
      "archived_at": "2019-12-27T18:11:19.117Z",
      "dataset_id": "dataset_id",
      "files": {
        "foo": "string"
      },
      "object": "dataset.item"
    }
  ],
  "object": "list"
}
```