Using Schemas to Define the Fields of Analytics Objects
You can import an Apache Avro schema file to define the field structure of your analytics object.
To import a schema file, your analytics object must not have any fields defined.
The namespace and object name in your schema file must match the name of the analytics object that you created.
* After you create your analytics object, click Import Schema.
The file browser dialog box appears.
* Select a valid Avro schema file from your computer and click Open.
For more information about Avro schemas, see Apache Avro.
The field structure defined in the schema file appears in the Fields section.
* Click Save.
The field structure defined in your Avro schema file is imported to your analytics object.
https://docs.oracle.com/en/cloud/paas/iot-cloud/iotgs/using-schemas-define-fields-analytics-objects.html