code: public String getAttributePropertyFromDB(final String attributeName, final String propertyName) throws DevFailed {
          xlogger.entry(propertyName);
          String[] result = new String[] {};
          final Map<String, String[]> prop = DatabaseFactory.getDatabase().getAttributeProperties(deviceName,
                  attributeName);
          if (prop.get(propertyName) != null) {
              // get value
              result = prop.get(propertyName);
              logger.debug(attributeName + " property {} is {}", propertyName, Arrays.toString(result));
          }
          xlogger.exit();
          String single = "";
          if (result.length == 1 && !result[0].isEmpty()) {
              single = result[0];
          }
          return single;
      }
docs: Get an attribute property from tango db
  
  @param attributeName
  @param propertyName
  @return The property
  @throws DevFailed