---
Title: Write to a Redis JSON document
aliases: /integrate/redis-data-integration/ingest/data-pipelines/transform-examples/redis-json-example/
alwaysopen: false
categories:
- docs
- integrate
- rs
- rdi
description: null
group: di
linkTitle: Write to a Redis JSON document
summary: Redis Data Integration keeps Redis in sync with the primary database in near
  real time.
type: integration
weight: 30
---

{{<note>}}
You must enable the [RedisJSON]({{< relref "/develop/data-types/json" >}}) module in the target Redis
database to use this feature.
{{</note>}}

In the example below, the data is captured from the source table named `invoice` and is written to the Redis database as a JSON document. The `connection` is an optional parameter that refers to the corresponding connection name defined in `config.yaml`. When you specify the `data_type` parameter for the job, it overrides the system-wide setting `target_data_type` defined in `config.yaml`. 

Another optional parameter, `on_update`, specifies the writing strategy. You can set this to either `replace` (the default) or `merge`. This affects the way the document is written to the target. Replacing the document will overwrite it completely, while merging will update it with the fields captured in the source, keeping the rest of the document intact. The `replace` option is usually more performant, while `merge` allows other jobs and applications to set extra fields in the same JSON documents. 

In this case, the result will be Redis JSON documents with key names based on the key expression (for example, `invoice_id:1`) and with an expiration of 100 seconds. If you don't supply an `expire` parameter, the keys will never expire.    

```yaml
name: Write invoice to JSON
source:
  schema: public
  table: invoice
output:
  - uses: redis.write
    with:
      connection: target
      data_type: json
      key:
        expression: concat(['invoice_id:', InvoiceId])
        language: jmespath
      on_update: replace
      expire: 100
```