In the PowerExchange CDC Publisher cdcPublisherAvro.cfg configuration file, you specify the Avro schema format type in the Formatter.avroSchemaFormat parameter. Options are:

Also, you can "wrap" a flat, nested, or generic schema in a "wrapper" schema by setting the

Formatter.avroWrapperSchemaFormat

property to

avroWrapperSchemaFormatV1

in the cdcPublisherAvro.cfg configuration file. The wrapper schema defines three fields for the following metadata: the change sequence number, the source

mapname

_

tablename

value from the extraction map name, and the change operation type. The wrapper schema also includes a field for the "wrapped" child schema, which is expressed as a large string.

A generic or wrapper schema can be used for multiple source objects. Consider using a generic or wrapper schema when you want to send messages with change data from multiple source objects to a single Kafka topic. The topic is identified in the Connector.kafkaTopic property.

A flat or nested schema pertains to a specific source table. It defines the columns in the source table. Consider using a flat or nested schema when you want to send change data from a specific source object to the topic that is generated for that source object. In this case, set the Connector.kafkaTopic property to USE_TABLE_NAME.

This appendix shows the general structure of the flat, nested, generic, and wrapper formats. It also describes the four Avro fields that are used to describe each source column or field in an Avro flat or nested schema.