Invoice Numbers with Series Prefixes

In this lesson, let's examine the database structure for invoice numbers. For example, an invoice number can start with a series or prefix and then a number leading with zeros, like INT-001.

Another example could be a year and then 001 after the dash, like 2024-001. Or some word and then the number, like Mars-108.

So, how do you store that in the database and make that incremental?

Eloquent Mutators

Imagine a simplified Invoice table where we save the invoice number in the invoice_number column.

Schema::create('invoices', function (Blueprint $table) {
    $table->id();
    $table->foreignId('user_id');
    $table->unsignedBigInteger('invoice_number');
    $table->integer('paid_total');
    $table->timestamps();
});

How do you set the invoice_number column to be incremented when the invoice is created? Probably the easiest way would be to use an Eloquent mutator.

app/Models/Invoice.php:

use Illuminate\Database\Eloquent\Casts\Attribute;
 
class Invoice extends Model
{
    protected $fillable = [
        'user_id',
        'invoice_number',
        'paid_total',
    ];
 
    public function user(): BelongsTo
    {
        return $this->belongsTo(User::class);
    }
 
    protected function invoiceNumber(): Attribute 
    {
        return Attribute::make(
            set: fn () => Invoice::max('invoice_number') + 1,
        );
    } 
}

The downside of this method is you still need to pass...