Account number help.

[684425]

I am trying to create a registration form where users put their name, email and password only.

 

but i want to write an auto generated account number into database table for each user e.g; XY1234567 where XY should not change 1234567 auto generated random number and no duplicates (in numbers only).

 

example...

 

XY1234567

XY2345678

XY2233455

 

i found code

$num_of_ids = 10000; //Number of "ids" to generate.
$i = 0; //Loop counter.
$n = 0; //"id" number piece.
$l = "AAA"; //"id" letter piece.

while ($i <= $num_of_ids) { 
    $id = $l . sprintf("%04d", $n); //Create "id". Sprintf pads the number to make it 4 digits.
    echo $id . "<br>"; //Print out the id.

    if ($n == 9999) { //Once the number reaches 9999, increase the letter by one and reset number to 0.
        $n = 0;
        $l++;
    }

    $i++; $n++; //Letters can be incremented the same as numbers. Adding 1 to "AAA" prints out "AAB".
}

but its not working as i want. Any help please?

[yozyk]

http://php.net/manual/en/function.uniqid.php

Is it what you are looking for?

[684425]

not this because it generates alphanumeric random output and i want XY(random, unique integer, fixed length) = XY9162942 or XY6433389

 

Sorry i forgot to mention fixed length in previous post.

[Jacques1]

Don't use code you found somewhere on the Internet. Most of it is crap.

 

Why do the numbers have to be random? Do they just have to be random-looking, or is it important that they are indeed unpredictable?

 

One thing is for sure: Random and unique and only 7 digits long will be difficult.

[hansford]

Not sure of what you want exactly, but I used your code.

<?php
$num_of_ids = 10000; //Number of "ids" to generate.
$i = 0; //Loop counter.
$n = 0; //"id" number piece.
$l = array("AAA","AAB","ABA","BBA","ABB","BBB","BAB","BAA"); //"id" letter piece.
$count = 0;

while ($i <= $num_of_ids)
{
    $id = $l[$count] . sprintf("%04d", $n); //Create "id". Sprintf pads the number to make it 4 digits.
    echo $id . "<br>"; //Print out the id.

    if ($n == 9999)
    {
        //Once the number reaches 9999, increase the letter by one and reset number to 0.
        $n = 0;
        $count++;

        if (count($l) == $count)
        {
            break;
        }

    }

    $n++; //Letters can be incremented the same as numbers. Adding 1 to "AAA" prints out "AAB".
}

[ginerjm]

You said it's not working.  Just what is it doing?  I ran it and got just what the code is setup to do.  It produces a sequence of numbers for trios of letters as in:

 

AAA0001

AAA0002

...

...

AAA9999

AAB0001

AAB0002

....

 

and so on.  That's what you coded.

[Jacques1]

I think the problem is that the sample code has absolutely nothing to do with the requirements. So instead of wasting our time with it, I'd rather start from scratch.

[hansford]

Each user is going to have a unique ID in the database - if that is tagged onto any sequence of random chars - the registration id will be unique.

Why do they even need a registration id - a temp registration number attached to a url that is emailed to them I can see, but that will expire and be deleted from the database.

[ginerjm]

Let's see what the OP has to say.

[684425]

  On 12/27/2014 at 6:20 PM, Jacques1 said:

Why do the numbers have to be random? Do they just have to be random-looking, or is it important that they are indeed unpredictable?

just random looking and unique, because a registered user will need that account number to login to his account.

 

  Quote

One thing is for sure: Random and unique and only 7 digits long will be difficult.

if possible and if you guide me, i want to do it. please guide   

[684425]

  On 12/27/2014 at 6:32 PM, ginerjm said:

You said it's not working as exactly i want. 

 

i have an account in skrill, they have given me an account number eg; XX12345678 which they generated automatically for me. and its unique for every registered user.

 

i want to do the same thing for users of my site.

[hansford]

<?php


// make db connection

$id = '';


while ( true )

{

    $id = uniqid(true);


    $query = "SELECT COUNT(*) FROM $table WHERE reg_id=$id";

    $stmt->execute($query);


    if (($stmt->fetchColumn()) == 0)

    {

        break;

    }

}

// we have a unique id compared to anything in the db

 

[Jacques1]

This doesn't work. If two PHP processes come up with the same new number at almost the same time, then they're both allowed to have it. You'll end up with a duplicate.

 

The uniqueness check must be done at database level with a UNIQUE constraint. You first try to insert the number, and if that fails, you try again with another number:

<?php

// MySQL error code
define('MYSQL_ER_DUP_ENTRY', 1062);

define('ACCOUNT_ID_PREFIX', 'XY');
define('ACCOUNT_NUMBER_LENGTH', 7);
define('MAX_RETRIES', 3);



// this should be in a separate file
$database = new PDO('mysql:host=localhost;dbname=YOUR_DB;charset=utf8mb4', 'YOUR_USER', 'YOUR_PW', [
    PDO::ATTR_EMULATE_PREPARES => false,
    PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION,
    PDO::ATTR_DEFAULT_FETCH_MODE => PDO::FETCH_ASSOC,
]);

$registration_stmt = $database->prepare('
    INSERT INTO
        users
    SET
        account_id = :account_id
');

/*
 * Generate a random account number and let the database check if it's unique. If the number is not unqiue, try again.
 * Give up after a certain number of attempts.
 */
$registration_successful = false;
$failed_attempts = 0;
while (!$registration_successful && $failed_attempts < MAX_RETRIES)
{
    try
    {
        /*
         * If l is the desired number of digits, the possible numbers range from 0 to 10**l - 1.
         * For example, if l = 7, then the number is in the interval 0..9999999
         */
        $account_number = mt_rand(0, pow(10, ACCOUNT_NUMBER_LENGTH) - 1);
        $account_id = ACCOUNT_ID_PREFIX . str_pad($account_number, ACCOUNT_NUMBER_LENGTH, '0', STR_PAD_LEFT);

        $registration_stmt->execute(['account_id' => $account_id]);
        $registration_successful = true;    // this is only executed if the query succeeded
    }
    catch (PDOException $registration_error)
    {
        $error_code = $registration_error->errorInfo[1];

        // If the error was due to a violation of the UNIQUE constraint, catch it and try again; otherwise rethrow it
        if ($error_code == MYSQL_ER_DUP_ENTRY)
        {
            $failed_attempts++;

            if ($failed_attempts == MAX_RETRIES)
            {
                throw new Exception('Gave up trying to generate unique account ID after ' . MAX_RETRIES . ' attempts. The pool might be exhausted.');
            }
        }
        else
        {
            throw $registration_error;
        }
    }
}

[hansford]

  Quote

 

 

The uniqueness check must be done at database level with a UNIQUE constraint

 

Absolutely. An id wouldn't be much good if it wasn't unique within the database.

If two concurrent processes attempt to create the same id - one of them will succeed the race condition and the other will fail with an error.