# What's the preferred way to update part of a nested document
**URL:** https://discuss.elastic.co/t/whats-the-preferred-way-to-update-part-of-a-nested-document/243705
**Category:** Elasticsearch
**Created:** [August 4, 2020, 12:36pm UTC](https://discuss.elastic.co/t/whats-the-preferred-way-to-update-part-of-a-nested-document/243705 "2020-08-04T12:36:26Z")
**Posts on this page:** 2
**Page:** 1
### Author:  [@viebel](https://discuss.elastic.co/u/viebel)
#### Post date: [August 4, 2020, 12:36pm UTC](https://discuss.elastic.co/t/whats-the-preferred-way-to-update-part-of-a-nested-document/243705/1 "2020-08-04T12:36:26Z")
My document has a nested structure like this:
```
PUT /customer/_doc/1
{
"name": "hello",
"body": {
"module": "aa",
"config": "bb"
}
}
```
Now, I'd like to update `body` field to be:
```
{
"module": "cc",
"args": "dd"
}
```
Pay attention I need to:
1. update the value associated to `module`
2. remove the `config` field
3. add an `args` field
I tried to use update API
```
POST /customer/_update/1
{
"doc": {
"body": {
"module": "cc",
"args": "dd"
}
}
}
```
It almost works, but the problem is that the `config` field is not removed
`GET /customer/_doc/1`
```
{
...
"_source" : {
"name" : "hello",
"body" : {
"module" : "cc",
"config" : "bb",
"args" : "dd"
}
}
```
}
Is the exact merging algorithm used by update API documented somewhere?
Is there a way to achieve this without writing a script?
I don't want to get the document, do the merge and ind it again ( I prefer to use the update API to avoid roundtrips and benefit from auto retry mechanism)
---
### Author:  [@system](https://discuss.elastic.co/u/system)
#### Post date: [September 1, 2020, 12:36pm UTC](https://discuss.elastic.co/t/whats-the-preferred-way-to-update-part-of-a-nested-document/243705/2 "2020-09-01T12:36:29Z")
This topic was automatically closed 28 days after the last reply. New replies are no longer allowed.