@Override
        public String render(Type columnType, List args, SessionFactoryImplementor factory) {
            if (args.get(1).equals("string")) {
                return super.render(columnType, Arrays.asList("char(" + args.get(0) + ")", args.get(1)), factory);
            } else {
                return super.render(columnType, args, factory);
            }
        }
{@code QDerbyDialect} extends {@code DerbyDialect} with additional functions
querydsl-jpa/src/main/java/com/querydsl/jpa/support/QDerbyDialect.java