问如何在不重复php中的每个用户的情况下创建唯一的用户ID(XXXX-NNNN)？

EN

    function bobby_tables()
    {
         $uni=uniqid(); //returns a unique string based on time

         $newuserid=time(); //returns a UNXI time stamp

         $uni=str_split($uni); //splits string in to an array

         //data set to convert numbers to alphabets
         $set= array('0'=>'A' ,'1' =>'B' ,'2'=>'C' ,'3'=>'D' ,'4'=>'E' ,'5'=>'F' ,'6'=>'G' ,'7'=>'H' ,'8'=>'I' ,'9'=>'J');

         $i=0; //to increment array value in loop

        //first loop converting a set of numbers to alphabets
        foreach ( $uni as $key1 => $value1)
        {
            foreach ( $set as $key2 =>$value2)
            {
                if ($value1==$key2)
                {
                    $newid[$i]=$value2;
                }
            }

            $i++; //incremental 
        }

        //second loop changing array to string
        foreach ($newid as $key => $value) 
        {
            $newuserid.= $value;
        }

        //reversing the string not really needed
        $newuserid=strrev($newuserid);

        return $newuserid; //return the end result
    }

    echo bobby_tables();