code: static function getDataType($value)
      {
          switch ($value) {
              case "string":
                  return self::$STRING;
              case "double":
                  return self::$DOUBLE;
              case "float":
                  return self::$FLOAT;
              case "integer":
                  return self::$INTEGER;
              case "boolean":
                  return self::$BOOLEAN;
              case "timestamp":
                  return self::$TIMESTAMP;
              case "json":
                  return self::$JSON;
  
              default:
                  return null;
          }
      }
docs: Get the permission object by type descriptor.
  
  @param string $value
  a type descriptor string. Can be "string", "double", "float",
  "integer", "boolean", "timestamp" or "json".
  @return \em DataType
  the DataType object