code: @Override
  	public TileMatrix queryForId(TileMatrixKey key) throws SQLException {
  		TileMatrix tileMatrix = null;
  		if (key != null) {
  			Map<String, Object> fieldValues = new HashMap<String, Object>();
  			fieldValues.put(TileMatrix.COLUMN_TABLE_NAME, key.getTableName());
  			fieldValues.put(TileMatrix.COLUMN_ZOOM_LEVEL, key.getZoomLevel());
  			List<TileMatrix> results = queryForFieldValues(fieldValues);
  			if (!results.isEmpty()) {
  				if (results.size() > 1) {
  					throw new SQLException(
  							"More than one TileMatrix returned for key. Table Name: "
  									+ key.getTableName() + ", Zoom Level: "
  									+ key.getZoomLevel());
  				}
  				tileMatrix = results.get(0);
  			}
  		}
  		return tileMatrix;
  	}
docs: {@inheritDoc}