code: public final String evSqlVl(
      final String pNm) throws ExceptionWithCode {
      Object val = evObjVl(pNm);
      if (val == null) {
        return "null";
      } else {
        return val.toString();
      }
    }
docs: <p>Evaluate column val for SQL statement INSERT or UPDATE.</p>
  @param pNm column name
  @return String column val
  @throws ExceptionWithCode if column not found