How to to create unique random integer ID for primary key for table?

Question

I was wondering if anybody knew a good way to create a unique random integer id for a primary key for a table. I\'m using MySQL. The value has to be integer.

Answer 1

There is an AUTO_INCREMENT feature. I would use that.

See here more examples.

Answer 2

my way, for both 32bit and 64bit platform. result is 64bit

function hexstr2decstr($hexstr){
    $bigint = gmp_init($hexstr, 16);
    $bigint_string = gmp_strval($bigint);
    return $bigint_string;
}

function generate_64bitid(){
    return substr(md5(uniqid(rand(), true)), 16, 16);
}

function dbGetUniqueXXXId(){
    for($i = 0; $i < 10; $i++){
        $decstr = hexstr2decstr(generate_64bitid());

        //check duplicate for mysql.tablexxx
        if($dup == false){
            return $decstr;
        }
    }
    return false;
}