code: private BoundStatement addColumnDelete(String tableName, String key, String colName) {
          PreparedStatement prepState = m_dbservice.getPreparedUpdate(Update.DELETE_COLUMN, tableName);
          BoundStatement boundState = prepState.bind();
          boundState.setString(0, key);
          boundState.setString(1, colName);
          return boundState;
      }
docs: Create and return a BoundStatement that deletes the given column.