code: @Override
      public String toString4Where(final Object _value)
          throws EFapsException
      {
          String ret = "";
          if (_value instanceof ReadableDateTime) {
              ret = Context.getDbType().getStr4DateTime((ReadableDateTime) _value);
          } else if (_value instanceof String) {
              ret = (String) _value;
          }
          return ret;
      }
docs: {@inheritDoc}