---
mapped_pages:
  - https://www.elastic.co/guide/en/elasticsearch/painless/current/painless-update-context.html
products:
  - id: painless
---

# Update context [painless-update-context]

Use a Painless script in an [update](https://www.elastic.co/docs/api/doc/elasticsearch/operation/operation-update) operation to add, modify, or delete fields within a single document.

**Variables**

`params` (`Map`, read-only)
:   User-defined parameters passed in as part of the query.

`ctx['op']` (`String`)
:   The name of the operation.

[`ctx['_routing']`](/reference/elasticsearch/mapping-reference/mapping-routing-field.md) (`String`, read-only)
:   The value used to select a shard for document storage.

[`ctx['_index']`](/reference/elasticsearch/mapping-reference/mapping-index-field.md) (`String`, read-only)
:   The name of the index.

[`ctx['_id']`](/reference/elasticsearch/mapping-reference/mapping-id-field.md) (`String`, read-only)
:   The unique document id.

`ctx['_version']` (`int`, read-only)
:   The current version of the document.

`ctx['_now']` (`long`, read-only)
:   The current timestamp in milliseconds.

[`ctx['_source']`](/reference/elasticsearch/mapping-reference/mapping-source-field.md) (`Map`)
:   Contains extracted JSON in a `Map` and `List` structure for the fields existing in a stored document.

**Side Effects**

`ctx['op']`
:   Use the default of `index` to update a document. Set to `none` to specify no operation or `delete` to delete the current document from the index.

[`ctx['_source']`](/reference/elasticsearch/mapping-reference/mapping-source-field.md)
:   Modify the values in the `Map/List` structure to add, modify, or delete the fields of a document.

**Return**

`void`
:   No expected return value.

**API**

The standard [Painless API](https://www.elastic.co/guide/en/elasticsearch/painless/current/painless-api-reference-shared.html) is available.

**Example**

To run this example, first follow the steps in [context examples](/reference/scripting-languages/painless/painless-context-examples.md).

The following query updates a document to be sold, and sets the cost to the actual price paid after discounts:

```console
POST /seats/_update/3
{
  "script": {
    "source": "ctx._source.sold = true; ctx._source.cost = params.sold_cost",
    "lang": "painless",
    "params": {
      "sold_cost": 26
    }
  }
}
```