Nasif Md. Tanjim Nasif Md. Tanjim - 4 years ago 297
SQL Question

How to generate unique random value for each user in laravel and add it to database

I am developing a event organization website. Here when the user registers for an event he will be given a unique random number(10 digit), which we use to generate a barcode and mail it to him. Now,

  1. I want to make the number unique for each registered event.

  2. And also random

One solution is to grab all the random numbers in an array and generate a random number using Php rand(1000000000, 9999999999) and loop through and check all the values. Grab the first value that doesn't equal to any of the values in the array and add it to the database.

But I am thinking that there might be a better solution to this. Any suggestion?

Answer Source

Your logic isn't technically faulty. However, if your application attracts lots of users, fetching all of the random numbers may well become unnecessarily expensive, in terms of resources and computation time.

I would suggest another approach, where you generate a random number and then check it against the database.

function generateBarcodeNumber() {
    $number = mt_rand(1000000000, 9999999999); // better than rand()

    // call the same function if the barcode exists already
    if (barcodeNumberExists($number)) {
        return generateBarcodeNumber();

    // otherwise, it's valid and can be used
    return $number;

function barcodeNumberExists($number) {
    // query the database and return a boolean
    // for instance, it might look like this in Laravel
    return User::whereBarcodeNumber($number)->exists();
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