CODEWITHSUNDEEP
phplaravelrandomunique
Majid Abdolhosseini
Majid Abdolhosseini

Reputation: 2301

Generate hundreds of random unique coupon codes and insert in database

I'm using PHP laravel 7 I have a coupons table which has a field called code, and this code is 8 characters (numbers and characters) this code should be unique among coupon records, In admin panel I have a button for admin user, which he can click on and generate as many coupons as he want. I'm gonna share with you the best solution came to my mind and ask you if there is a better and more performant solution.

I'm gonna generate unique strings in my php code using following function :

substr(uniqid(), 0, 8)

then I'll execute a query to check if there is any coupons in my table which it's code is equal to one of my newly generated codes

$model->newQuery()->whereIn('code', $generated_codes)->get();

if the result list is empty, that's nice I'm gonna insert all of my codes in database. if the list is not empty, I'm gonna delete repeated codes from my generated codes, and also again based on number of repeated codes again generate new codes and again repeat the process, I'm gonna repeat the process as long as none of generated codes exist in database then I insert them in database.

my question is different from this question: PHP: How to generate a random, unique, alphanumeric string?

As I'm generating lots of unique codes, not just on code, and then I'm gonna insert these codes in database and I need to have minimum number of queries.

Upvotes: 0

Views: 2715

Answers (3)

apokryfos
apokryfos

Reputation: 40690

Here's something something that might work:

function generateRandomCodes($number) {
    $codes = Collection::times($number, function () { Str::random(8); });

    $affected = DB::table('your_table')
       ->insertOrIgnore($codes->map(function ($code) {
             return [ 'code' => $code, /* more fields? */ ];
       });
    if ($affected < $number) {
        generateRandomCodes($number-$affected);  
    }
}

insertOrIgnore will ignore duplicate keys when inserting and overwrite data. This is useful because it avoids a lookup before the insert which can be expensive, this should return number of affected rows, i.e. new rows created. If it does not manage to insert all desired codes then it should run it again for the remaining codes. This all assumes that code is the primary key.

I have not tested this myself so I suggest you test it before using it in any production code.

Some additional notes:

Str::random internally uses a base64 encoded string from random_bytes which is cryptographically secure (though not sure if the base64 version of it would technically count as secure nor if the final result is actually secure). This means there are 62^8 = 2*10^14 combinations you can get characters (+, = and / are removed). That is an insanely high number and you shouldn't really expect collisions to happen until you've generated about 10% of those numbers (about 2*10^13) however this assumes you are storing these in a case sensitive column in your database, and by default string columns are not case sensitive, which cuts your unique combinations by about two thirds (which is still a quite large number) meaning you will not really need to call this function more than once unless you really are that "lucky"

Upvotes: 2

Odin Thunder
Odin Thunder

Reputation: 3547

U can use firstOrCreate(), but in fact it may execute a lot of query to. Hope it help U to find good solution

public function initCoupon()
{
    $code = substr(uniqid(), 0, 8);
    $new = false;
    do {

        $coupon = CouponModel::firstOrCreate(compact('code'));
        $new = $coupon->wasRecentlyCreated

    } while(!$new);

    return $coupon;
}

Than U can set additional Coupon data

Upvotes: 0

Nishabh Mistry
Nishabh Mistry

Reputation: 59

You can use this type of function to get unique coupon code.

function generateCode(){

    $code = substr(uniqid(), 0, 8);
    $exists = YourModel::where('code', $code)->count();
    if($exists > 0){
        $this->generateCode();
    }
    return $code;
}

Upvotes: 0

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