Contao - Create a Unique Key by a char set

generateUniqueKey.php

<?php

public static function generateUniqueId()
    {
        $charSet = "ABCDEFGHJKLMNPQRSTUVWXYZ123456789";

        $position = 0;
        $uniqueId = '';
        for ($i = 0; $i < 6; $i++)
        {
            $position = ($position + rand(1000, 9999)) % strlen($charSet);
            $uniqueId .= $charSet[$position];
        }

        # UNIQUE ID muss einzigartig sein und darf nicht bereits in der Datenbank vorhanden sein
        $uniquIdResult = \Database::getInstance()
            ->prepare("SELECT * FROM tl_member WHERE uniqueid like ? ")
            ->execute( $uniqueId );
    
        if ($uniquIdResult->numRows > 0 )
        {
            $uniqueId = self::generateUniqueId();
        }

        return $uniqueId;
    }