Query on Flink SQL primary key for nested field

Question

I have a Kafka topic named employee which uses confluent avro schema and will emit the payload as below:

{
"employee": {
"id": "123456",
"name": "sampleName"
}
}

I am using Apache Flink's upsert-kafka connector to consume the events from the above Kafka topic as below using the Flink SQL DDL statement, also here I want to use the id field as the Primary key. But I am unable to use the id field since it is inside the object.

DDL Statement:

String statement = "CREATE TABLE Employee (\r\n" +
"  employee  ROW(id STRING, name STRING\r\n" +
"  ),\r\n" +
"  PRIMARY KEY (employee.id) NOT ENFORCED\r\n" +
") WITH (\r\n" +
"  'connector' = 'upsert-kafka',\r\n" +
"  'topic' = 'employee',\r\n" +
"  'properties.bootstrap.servers' = 'kafka-cp-kafka:9092',\r\n" +
"  'key.format' = 'raw',\r\n" +
"  'value.format' = 'avro-confluent',\r\n" +
"  'value.avro-confluent.url' = 'http://kafka-cp-schema-registry:8081',\r\n" +
")";