public Parser identifiedByStatement() {
        if (identifiedByStatementParser == null) {
           FutureParser future = scoped("identifiedByStatement");
           identifiedByStatementParser = future;
           future.setParser(
               sequence(
                   token("IDENTIFIED"),
                   optional(
                       token("BY")
                   ),
                   choice(
                       dataName(),
                       literal()
                   ),
                   optional(
                       sequence(
                           optional(
                               token("IS")
                           ),
                           token("ATTRIBUTE")
                       )
                   )
               )
           );
        }

        return identifiedByStatementParser;
    }