public static SamzaSqlRelRecord createSamzaSqlCompositeKey(SamzaSqlRelMessage message, List<Integer> relIdx) {
    return createSamzaSqlCompositeKey(message, relIdx,
        getSamzaSqlCompositeKeyFieldNames(message.getSamzaSqlRelRecord().getFieldNames(), relIdx));
  }
Create composite key from the rel message.
@param message Represents the samza sql rel message to extract the key values and names from.
@param relIdx list of keys in the form of field indices within the rel message.
@return the composite key of the rel message
samza-sql/src/main/java/org/apache/samza/sql/data/SamzaSqlRelMessage.java