Kafka uses a key-value-pair data model. Key and value are independent
from each other.
Thus, you cannot define a single column (ie, single STRUCT) that spans
over key and value, because each column must either be mapped into the
key or the value of the underlying key-value-pair.
So in your example, you define a STRUCT `structure` and thus `structure`
is a column that lives either in the key or the value.
Why do you want/need to define a STRUCT that spans over key and value?
-Matthias
On 9/7/21 10:37 AM, Greer, Andrew C wrote:
> Hello all,
>
>
> I was wondering if it is possible to add the message key value to a structure
> in KSQL. My coworker has a specific need where the key values of the messages
> should be in the same structure as the other values he is collecting.
>
>
> We were hoping something like this would work, but it will not accept that as
> a value:
> CREATE STREAM PI_STREAM_01 ("Structure" STRUCT<"keyValue" VARCHAR KEY,
> "Value" VARCHAR>) WITH (KAFKA_TOPIC='lift_twelve', VALUE_FORMAT='KAFKA');
>
>
> Thank you,
>
> Andrew Greer
>
>
