Doctrine\ODM\MongoDB\Mapping\MappingException::identifierRequired PHP Метод

    public static function identifierRequired($documentName)
    {
        return new self("No identifier/primary key specified for Document '{$documentName}'." . ' Every Document must have an identifier/primary key.');
    }

 /**
  * Validates the identifier mapping.
  *
  * @param ClassMetadata $class
  */
 protected function validateIdentifier($class)
 {
     if (!$class->identifier && !$class->isMappedSuperclass && !$class->isEmbeddedDocument) {
         throw MappingException::identifierRequired($class->name);
     }
 }