@Override
  public void readFields(DataInput dataInput) throws IOException {
    dbName = (String)ReaderWriter.readDatum(dataInput);
    eventId = (Long) ReaderWriter.readDatum(dataInput);
  }
Trivial ctor to support Writable reflections instantiation
do not expect to use this object as-is, unless you call
readFields after using this ctor
hcatalog/webhcat/java-client/src/main/java/org/apache/hive/hcatalog/api/repl/commands/DropDatabaseCommand.java