private function addIdentifierCondition(
        array $identifier,
        array &$columns,
        array &$values,
        array &$conditions
    ) : void {
        $platform = $this->getDatabasePlatform();

        foreach ($identifier as $columnName => $value) {
            if ($value === null) {
                $conditions[] = $platform->getIsNullExpression($columnName);
                continue;
            }

            $columns[]    = $columnName;
            $values[]     = $value;
            $conditions[] = $columnName . ' = ?';
        }
    }