Merge pull request #494 from redis/DOC-4014-rdi-string-job-file

DOC-4014 added RDI string job config example

Author: andy-stark-redis

content/integrate/redis-data-integration/ingest/data-pipelines/transform-examples/redis-string-example.md

@@ -0,0 +1,52 @@
+---
+Title: Write to a Redis string
+aliases: null
+alwaysopen: false
+categories:
+- docs
+- integrate
+- rs
+- rdi
+description: null
+group: di
+linkTitle: Write to a Redis string
+summary: Redis Data Integration keeps Redis in sync with the primary database in near
+  real time.
+type: integration
+weight: 30
+---
+
+The string data type is useful for capturing a string representation of a single column from
+a source table.
+
+In the example job below, the `title` column is captured from the `invoice` table in the source.
+The `title` is then written to the Redis target database as a string under a custom key of the
+form `AlbumTitle:42`, where the `42` is the primary key value of the table (the `albumid` column).
+
+The `connection` is an optional parameter that refers to the corresponding connection name defined in
+[`config.yaml`]({{< relref "/integrate/redis-data-integration/ingest/data-pipelines/data-pipelines#the-configyaml-file" >}}). 
+When you specify the `data_type` parameter for the job, it overrides the system-wide setting `target_data_type` defined in `config.yaml`. Here, the `string` data type also requires an `args` subsection
+with a `value` argument that specifies the column you want to capture from the source table.
+
+The optional `expire` parameter sets the length of time, in seconds, that a new key will
+persist for after it is created (here, it is 86400 seconds, which equals one day).
+After this time, the key will be deleted automatically.
+If you don't supply an `expire` parameter, the keys will never expire. 
+
+```yaml
+source:
+  server_name: chinook
+  table: album
+  row_format: full
+output:
+  - uses: redis.write
+    with:
+      connection: target
+      data_type: string
+      key:
+        expression: concat(['AlbumTitle:', values(key)[0]])
+        language: jmespath
+      args:
+        value: title
+      expire: 86400
+```