code: private Number getIdColumnData(ResultSet resultSet, ResultSetMetaData metaData, int columnIndex)
  			throws SQLException {
  		int typeVal = metaData.getColumnType(columnIndex);
  		switch (typeVal) {
  			case Types.BIGINT:
  			case Types.DECIMAL:
  			case Types.NUMERIC:
  				return (Number) resultSet.getLong(columnIndex);
  			case Types.INTEGER:
  				return (Number) resultSet.getInt(columnIndex);
  			default:
  				String columnName = metaData.getColumnName(columnIndex);
  				throw new SQLException(
  						"Unexpected ID column type " + TypeValMapper.getSqlTypeForTypeVal(typeVal) + " (typeVal "
  								+ typeVal + ") in column " + columnName + "(#" + columnIndex + ") is not a number");
  		}
  	}
docs: Return the id associated with the column.