docs: @Override
      public boolean supportsConvert(int fromType, int toType) throws SQLException {
          checkClosed();
          switch (fromType) {
          /*
           * ALL types can be converted to VARCHAR /VoltType.String
           */
          case java.sql.Types.VARCHAR:
          case java.sql.Types.VARBINARY:
          case java.sql.Types.TIMESTAMP:
          case java.sql.Types.OTHER:
              switch (toType) {
              case java.sql.Types.VARCHAR:
                  return true;
  
              default:
                  return false;
              }
          case java.sql.Types.TINYINT:
          case java.sql.Types.SMALLINT:
          case java.sql.Types.INTEGER:
          case java.sql.Types.BIGINT:
          case java.sql.Types.FLOAT:
          case java.sql.Types.DECIMAL:
              switch (toType) {
              case java.sql.Types.VARCHAR:
              case java.sql.Types.TINYINT:
              case java.sql.Types.SMALLINT:
              case java.sql.Types.INTEGER:
              case java.sql.Types.BIGINT:
              case java.sql.Types.FLOAT:
              case java.sql.Types.DECIMAL:
                  return true;
  
              default:
                  return false;
              }
          default:
              return false;
          }
      }