docs: private String buildSelectClause() {
          StringBuilder sqlBuf = new StringBuilder();
  
          sqlBuf.append("SELECT ");
  
          String column = null;
          for (Enumeration select = mColumns.elements(); select.hasMoreElements();) {
              column = (String) select.nextElement();
  
              /*
                String subColumn = column.substring(column.indexOf(".") + 1);
                // System.err.println("DEBUG: col=" + subColumn);
                String mapType = (String) mMapTypes.get(mColumnMap.get(subColumn));
              */
              String mapType = (String) mMapTypes.get(getProperty(column));
  
              if (mapType == null || mapType.equals(DIRECTMAP)) {
                  sqlBuf.append(column);
  
                  sqlBuf.append(select.hasMoreElements() ? ", " : " ");
              }
          }
  	
          return sqlBuf.toString();
      }