CODEWITHSUNDEEP
php
siannone
siannone

Reputation: 6763

How can I generate a progressive sequential unique id in PHP?

How can I generate a progressive sequential unique id in PHP?

For example, the order should be this:

aaaaaa < aaaaab < aaaaac etc...

Upvotes: 3

Views: 9314

Answers (4)

aalaap
aalaap

Reputation: 4401

If you use any of the other solutions here, you'll still have to fetch or save the last id and then increment it. Instead, you could simply use the auto-incremented id and convert it into a textual representation.

I'm using Laravel examples here, but you can apply the theory to any framework.

// Save your model.
$flight = new Flight;
$flight->name = $request->name;
$flight->save();

// $flight->id now contains the last inserted id.
echo base_convert($flight->id, 10, 36);

// Output: 1E86

Base 10 is numbers from 0-9. Base 36 adds the 26 letters of the alphabet to that.

Note that there is no need to actually save the output back to the database, which would take another query and defeat the purpose of this optimisation. Instead, you can add a mutator that converts the id in real time:

class Flight extends Model {
    ...
    public function getUniqueIdAttribute()
    {
        return base_convert($this->id, 10, 36);
    }
}

Now you can simply save your model and call $flight->uniqueId and get your base 36 converted id.

Tip: Add a salt value to the id to prevent leaking actual database ids.

Upvotes: 0

Baba
Baba

Reputation: 95101

This is by default in PHP Incrementing/Decrementing Operators can work directly with Strings please see http://php.net/manual/en/language.operators.increment.php

$start = "aaaaaa" ;
$start++;
$start++;
var_dump($start);

Output

  string 'aaaaac' (length=6)

Upvotes: 6

goat
goat

Reputation: 31813

$id = 'aaaax';
for ($i=0; $i<100; $i++) {
    $id++;
    echo "$id\n";
}

demo http://codepad.org/ogGrOfyQ

Upvotes: 1

Niet the Dark Absol
Niet the Dark Absol

Reputation: 324620

uniqid() is increasing (an ID generated later will always be greater than one generated earlier) but will not be sequential (there will be gaps).

Otherwise, find a way to save the last generated ID, and increment it when you generate a new one.

Upvotes: 8

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