Hands On: Converting Data Formats with ksqlDB

Hands On: Converting Data Formats with ksqlDB

This exercise will teach you how to change data formats in ksqlDB.

Inspect Your Existing Data

1. Begin by printing your orders_flat stream from Hands On: Flatten Nested Records with ksqlDB to show the existing JSON data:

   PRINT orders_flat FROM BEGINNING;

   Click Run query.

2. Stop the query. Then expand a record to see the JSON structure.

Change Your Data's Format and Inspect It Again

3. Enter a CREATE STREAM AS statement, with VALUE_FORMAT set to delimited:

   CREATE STREAM orders_csv
   WITH(VALUE_FORMAT='delimited', KAFKA_TOPIC='orders_csv') AS
   SELECT * FROM orders_flat EMIT CHANGES;

   Click Run query. This will help to clean up the JSON you saw in Step 2.

4. Run a PRINT statement to see your newly delimited data:

   PRINT orders_csv FROM BEGINNING;

   Click Run query, then scroll down and expand a record to see the comma-delimited fields.

   It's as easy as that: VALUE_FORMAT helps you to change formats within ksqlDB.