> ## Documentation Index
> Fetch the complete documentation index at: https://docs.ub.bitbros.in/llms.txt
> Use this file to discover all available pages before exploring further.

# Update Document

> Update an existing document in a collection using PUT (full update) or PATCH (partial update).

Both `PUT` and `PATCH` update an existing document by ID. You only need to send the fields you want to change — unmentioned fields are left unchanged.

## PUT `/api/data/:collectionName/:id`

Typically used for full logical updates. Send only the fields you intend to change; fields you omit are left unchanged.

## PATCH `/api/data/:collectionName/:id`

Explicitly signals a partial update. Semantically equivalent to `PUT` in urBackend — both merge changes into the existing document without replacing unmentioned fields.

<Note>
  Nested field updates using dot notation are supported.
  For example, sending `"meta.views": 105` updates only the `views` key inside the `meta` object
  without affecting any other keys in `meta`.
</Note>

### Required header

`x-api-key`: `sk_live_…` by default. `pk_live_…` is accepted only when the collection has **RLS enabled** and the request includes `Authorization: Bearer <accessToken>`.

### Path parameters

<ParamField path="collectionName" type="string" required>
  The name of the collection containing the document.
</ParamField>

<ParamField path="id" type="string" required>
  The MongoDB ObjectId string of the document to update.
</ParamField>

### Request body

A JSON object containing the fields to update and their new values.

<Warning>
  The owner field (e.g., `userId`) is **immutable**. If you include it in the request body with
  a different value, the request is rejected with `403 Owner field immutable`. Remove it from
  the update body entirely.
</Warning>

### RLS behavior

When using `pk_live` with RLS enabled, urBackend fetches the existing document and compares its owner field against the authenticated user's ID. If they don't match, the request is rejected with `403`.

### Response fields

<ResponseField name="message" type="string">
  Confirmation message, returns `"Updated"` on success.
</ResponseField>

<ResponseField name="data" type="object">
  The updated document with all current field values.
</ResponseField>

### Code examples

<CodeGroup>
  ```javascript PUT — full update theme={null}
  const postId = '64fd1234abcd5678ef901234';

  const res = await fetch(
    `https://api.ub.bitbros.in/api/data/posts/${postId}`,
    {
      method: 'PUT',
      headers: {
        'Content-Type': 'application/json',
        'x-api-key': 'sk_live_YOUR_SECRET_KEY'
      },
      body: JSON.stringify({
        title: 'Updated title',
        'meta.views': 105   // Dot notation updates nested fields safely
      })
    }
  );

  const { data } = await res.json();
  console.log('Updated document:', data);
  ```

  ```javascript PATCH — partial update theme={null}
  const postId = '64fd1234abcd5678ef901234';

  const res = await fetch(
    `https://api.ub.bitbros.in/api/data/posts/${postId}`,
    {
      method: 'PATCH',
      headers: {
        'Content-Type': 'application/json',
        'x-api-key': 'sk_live_YOUR_SECRET_KEY'
      },
      body: JSON.stringify({
        title: 'Edited title only'
      })
    }
  );

  const { data } = await res.json();
  console.log('Updated document:', data);
  ```

  ```javascript pk_live + RLS (client-side) theme={null}
  const postId = '64fd1234abcd5678ef901234';

  const res = await fetch(
    `https://api.ub.bitbros.in/api/data/posts/${postId}`,
    {
      method: 'PATCH',
      headers: {
        'Content-Type': 'application/json',
        'x-api-key': 'pk_live_YOUR_KEY',
        'Authorization': `Bearer ${accessToken}`
      },
      body: JSON.stringify({
        title: 'My updated title'
        // Do NOT include the owner field here
      })
    }
  );

  const { data } = await res.json();
  console.log('Updated document:', data);
  ```

  ```bash curl theme={null}
  curl -X PUT "https://api.ub.bitbros.in/api/data/posts/64fd1234abcd5678ef901234" \
    -H "Content-Type: application/json" \
    -H "x-api-key: sk_live_YOUR_SECRET_KEY" \
    -d '{"title": "Updated title", "meta.views": 105}'
  ```
</CodeGroup>

### Success response

```json theme={null}
{
  "message": "Updated",
  "data": {
    "_id": "64fd1234abcd5678ef901234",
    "title": "Updated title",
    "body": "Content goes here...",
    "meta": {
      "views": 105,
      "likes": 12
    },
    "userId": "64fd0000abcd5678ef900001",
    "isDeleted": false,
    "deletedAt": null,
    "createdAt": "2024-01-15T10:30:00.000Z",
    "updatedAt": "2024-01-15T11:00:00.000Z"
  }
}
```

### Errors

| Status             | Cause                                                                             |
| :----------------- | :-------------------------------------------------------------------------------- |
| `400 Bad Request`  | Schema validation failed                                                          |
| `401 Unauthorized` | Missing/invalid API key, or missing Bearer token on an RLS-enabled collection     |
| `403 Forbidden`    | `pk_live` without RLS, owner field mismatch, or attempt to change the owner field |
| `404 Not Found`    | No document with that ID exists                                                   |