protected int possiblyAddColVar(CycVariable colVar) {
    String col = colVar.toString();
    int colIndex = -1;
    List<String> columnNames = getColumnNamesUnsafe();
    if ((colIndex = columnNames.indexOf(col)) < 0) {
      columnNames.add(col);
      for (List<Object> row : getRS()) {
        row.add(null);
      }
      return columnNames.size() - 1;
    }
    return colIndex;
  }